What should I do? 

That's the question that's on the mind of many investors right now. Fears about the global coronavirus outbreak have caused a market correction. A natural instinct is to flee -- run as fast as you can away from the stock market. But I suspect most investors know that this natural instinct isn't the best choice. The smarter approach is to take advantage of the buying opportunity that the market correction presents.

And that leads to another question: What stocks should I buy? There are actually plenty of good answers to that question because there are plenty of great stocks.

My view is that there are three kinds of stocks that you should consider buying during the market downturn. First, look at stocks that have held up well despite the overall market downturn -- the exceptions to the rule. Second, check out stocks that are dirt cheap because of the correction. And third, invest in stocks that are simply great businesses to own no matter what happens with the overall market. 

If you have some available cash, I think that investing $1,000 in each of the following three stocks that represent each of those categories is a great place to start.

One lighted white arrow pointing up with four blue arrows pointing down

Image source: Getty Images.

1. An exception to the rule

Few stocks have been able to defy the gravity of the overall stock market decline in recent days. But Gilead Sciences (NASDAQ:GILD) is one of them. It helped a lot that a World Health Organization (WHO) official stated recently that Gilead's experimental drug remdesivir appears to have the most potential in being effective at treating COVID-19, the disease caused by the novel coronavirus.

While Gilead's promising antiviral drug remdesivir is the reason why the stock has risen by a double-digit percentage this year, it's not the main reason I like the biotech stock. There are actually four other things that I like even more about Gilead than its coronavirus program. The first three relate to the company's current drugs and pipeline candidates.

Gilead continues to be a juggernaut in HIV. Biktarvy appears destined to become the most successful HIV drug in history. Thanks to the company's 2017 acquisition of Kite Pharma, Gilead is a leader in cancer cell therapy -- an area that I think will gain momentum in the future. The biotech is also poised to enter the immunology market if filgotinib wins FDA approval later this year in treating rheumatoid arthritis. Some analysts project that filgotinib could generate peak annual sales of close to $6 billion if approved for multiple indications.

That leaves the fourth reason I like Gilead: Its dividend. Most biotechs don't pay dividends, but Gilead is yet again an exception to the rule. Its dividend yield currently stands at close to 3.6%. Gilead has increased its dividend payout by 58% since initiating its dividend program in 2015. With more dividend increases probably on the way and growth drivers in HIV, oncology, and immunology (plus potentially with its coronavirus drug), Gilead should provide market-beating returns over the long run.

2. A dirt cheap bargain

TD Ameritrade Holding (NASDAQ:AMTD) has fallen hard during the market downturn. Shares of the online brokerage are down nearly 30%, a significantly worse performance than its peers. TD Ameritrade stock now trades at less than 14 times expected earnings.

Granted, it's not just worries about the coronavirus outbreak that have caused TD Ameritrade's stock to drop. The antitrust division of the Department of Justice is investigating the pending acquisition of TD Ameritrade by Charles Schwab (NYSE:SCHW). There's a possibility that the deal could be blocked.

But those fears could be overblown. Schwab and TD Ameritrade say they're cooperating fully with the DOJ and expect the transaction to close in the second half of this year. 

What if the DOJ prevents the acquisition? I still think the future for TD Ameritrade looks bright. Investors continue to flock to online brokerages. The greatest generational transfer of wealth is on the way. Research firm Cerulli Associates estimates that over the next 25 years $68 trillion will shift from older parents to their children. A lot of that money will be invested in stocks, creating a major opportunity for TD Ameritrade whether it remains an independent entity or not.

3. Just a great business to own

Last -- and certainly not least -- Brookfield Infrastructure Partners (NYSE:BIP) is just a great business to own. I'd make that claim even if the stock hasn't performed pretty well this year (which it has).

If you can think of a type of infrastructure asset, Brookfield Infrastructure probably owns it. Cell towers, data centers, electricity transmission systems, natural gas pipelines, ports, railroads, toll roads, and more are all in the company's portfolio.

I personally bought shares of Brookfield Infrastructure earlier this year, mainly because I think the company's business model is rock-solid. Brookfield doesn't have to worry about a viral epidemic impacting its financial strength. Close to 95% of its adjusted EBITDA comes from regulated or contracted revenue that won't change with twists and turns in the overall economy.

Brookfield Infrastructure also pays a dividend that yields more than 4%. The company has boosted its dividend payout by 52% over the last five years. With Brookfield's strategy of selling lower-performing assets to reinvest in more promising assets, I look for solid earnings growth plus more dividend increases in the future.