After smartphone shipments in China nearly quadrupled in the past two years, IDC says growth in the region will slow dramatically in the next few years. IDC estimates 2014 year-over-year growth in China smartphone sales of about 20% and just 10% in 2015. With such a significant slowdown in smartphone sales in the region, should Apple (NASDAQ:AAPL) investors be worried? After all, its Greater China segment accounts for a meaningful 15.3% of the company's sales (and growing).

In the video below, Fool contributor Daniel Sparks argues that despite slowing smartphone market growth in China, the country is still Apple's biggest opportunity. While it might not be enough to get investors with a short-term time horizon excited, the opportunity over the long haul is big enough to justify Apple's conservative valuation.