For millions, the Patient Protection and Affordable Care Act, also known as Obamacare, has been extremely difficult to understand. Now, Medicare recipients run the risk of missing out on making an important choice about their coverage if they don't act soon, in large part because of confusion about how Obamacare affects them.

In the following video, Dan Caplinger, The Motley Fool's director of investment planning, discusses how, unlike the later deadline for Obamacare enrollment, open enrollment for Medicare actually closes on December 7. As Dan notes, that leaves only a short time before Medicare recipients have to make decisions about Plan D prescription drug coverage plans for 2014. He points out that making the right choice can cut your overall medical expenses, as sometimes choosing a higher-premium plan provides enough savings on prescription drugs and other services to offset the extra cost.

Dan goes through some of the companies that provide Medicare prescription-drug plan coverage. In addition to traditional insurers UnitedHealth (NYSE:UNH) and Humana (NYSE:HUM), he notes that Express Scripts (NASDAQ:ESRX) and Rite Aid (NYSE:RAD) are also involved in the Plan D marketplace as well.