Which of the Following Statements About Breeding Systems Is True

Which of the following statements about breeding systems is true?

A) Genetic analyses of parentage have not furthered our understanding of mating systems.
B) The occurrence of extrapair copulations triggered ethologists to consider the difference between social and genetic monogamy.
C) Mating systems are classified solely on the basis of pairbond formation.
D) Within a species, only one type of mating system can evolve.
E) All human populations adhere to strict monogamy, that is, both social monogamy and genetic monogamy.