In katydids, male parental investment consists of the gift of a protein-rich nuptial meal in the form of a spermatophore.

A) The gift is especially important to females when food is scarce, and during these times females compete for males.
B) The spermatophore is important to successful reproduction because both the number and fitness of the female's offspring are enhanced by the male's gift.
C) When food is plentiful the relative value of the gift declines, and males compete for females.
D) All of the above.