When Biologists Bradshaw and Schemske Studied the Genetic Makeup of Mimulus

When biologists Bradshaw and Schemske studied the genetic makeup of Mimulus lewisii and Mimulus cardinalis,what hypothesis were they testing?

A) M. lewisii and M cardinalis are different species.
B) Mutation in a single gene could cause a change in flower color and thus pollinator.
C) M. lewisii and M cardinalis are the same species.
D) Mutation in multiple genes over a long period of time is required to change flower color and pollinators.
E) Pollinators do not choose which flowers to pollinate based on color.