Researchers Suspect That the Gene FOXP2, Which Is Involved in Speech

Researchers suspect that the gene FOXP2, which is involved in speech and cognition, has been under positive selection in the human lineage. Which of the following would provide the strongest support for such a claim?

A) The gene shows evidence of bioprospecting.
B) There is a higher rate of nonsynonymous substitutions than synonymous ones.
C) There is a lower rate of nonsynonymous substitutions than synonymous ones.
D) The gene evolves following the molecular clock.
E) There have been more transitions than transversions in the gene.