Which of the Following Explains Why a Loss of Biosynthetic

Which of the following explains why a loss of biosynthetic ability can be beneficial to an animal?

A) Once an animal obtains essential nutrients in its diet it can afford to lose the ability to synthesize those molecules.
B) Loss of biosynthetic ability confers a selective advantage to an animal.
C) As the diet of an animal became more varied, it loses its ability to synthesize available molecules such as amino acids.
D) All of the above are correct answers.