The Findings That Male Field Crickets Increase the Refractory Period

Multiple Choice

The findings that male field crickets increase the refractory period rather than produce smaller spermatophores between successive matings, that the costs of spermatophore production reduce the life span in male stalk-eyed flies, and that sperm counts decrease in successive ejaculates in male deer mice suggest that

A) costs to males associated with producing sperm and secretions from accessory glands are fairly trivial.
B) male selectivity is rare.
C) males remain undiscriminatingly eager in the allocation of ejaculates.
D) sperm supplies may be limited.