"which group is most likely to vote in a presidential election? "

In the United States, the oldest citizens are the most likely to cast their ballots, which gives them political clout beyond their numbers alone. Some 61 percent of citizens age 65 and older voted in the November 2010 election, the best turnout of any age group. More than half (54 percent) of those ages 55 to 64 also cast a ballot.

The answer to your question would be b