Water Fleas of the Genus Daphnia Can Switch from a Pattern

Water fleas of the genus Daphnia can switch from a pattern of asexual reproduction to sexual reproduction. This change would be more likely to occur under which of the following conditions?

A) when environmental conditions become more favorable for offspring
B) when temperatures change in ways that stress the adults
C) when food resources for offspring increase in abundance
D) when adults can no longer produce eggs