College students are more likely than their peers to _______.​

A) ​smoke cigarettes
B) ​drive after drinking
C) ​use cell phones while driving
D) ​engage in both behaviors b and c

While it is not specified that college students engage in any of these behaviors more often than their peers, the question asks for the likelihood of these behaviors. Research suggests that college students are more likely to engage in risky behaviors such as driving after drinking and using cell phones while driving. Therefore, the best choice is D, as it includes both of these behaviors.