According to Recent Research with College Populations What Was Found

According to recent research with college populations what was found related to sperm production?

A) Sperm production was highest for college males who had several sexual partners.
B) Sperm production was lower during exam periods than at the beginning of the semester.
C) Sperm production was higher in students attending college in cooler climates (e.g., Minnesota, New York) than those attending college in warmer parts of the U.S. (e.g., Florida, Texas) .
D) Sperm production was highest for college males who masturbated daily.