After dating her boyfriend for only three weeks, thirty-eight-year-old Carla was excited that she was getting married, despite the fact that a few days before, she was not sure if they had much in common. Carla's decision seems to be ________

a. an example of the parental imperative
b. evidence of crossover of gender roles
c. dictated by the social clock
d. an example of the marital selection effect

C