In an Analysis of Independent Contrast, Researchers Found That Fetuses

In an analysis of independent contrast, researchers found that fetuses in polyandrous species of primates had faster growth rates than those in monogamous species. What did the researchers conclude from these results?

A) Fetuses develop faster to "make room" for offspring from a different male.
B) Extracting more resources from the mother maximizes offspring's inclusive fitness in polyandrous species.
C) Fast fetal growth rates are always optimal.
D) Fetal growth rates represent phylogenetic constraints and are unrelated to mating systems.