Which of these hypotheses in evolutionary psychology is most controversial?

a. Kittiwake chicks have evolved a tendency to remain motionless until old enough to fly.
b. We get goose bumps when we are cold because the response helped our ancestors.
c. Human infants' grasp reflex is an evolutionary carryover from monkeylike ancestors.
d. Men seek multiple sex partners because doing so can spread their genes.

d