Male and female preference for symmetrical faces in potential mates is thought to be due to the fact that

A) mating cues are often completely arbitrary.
B) people with symmetrical faces are less likely to be unfaithful.
C) people don't want their children to inherit an asymmetrical face.
D) symmetry suggests that a potential mate is genetically healthy.

Answer: D
Rationale: In evolutionary terms, symmetry is hypothesized to be a physical display of mate quality because it signals that the individual is genetically healthy.