Two True-Breeding Mutant Strains of Drosophila Have Black Body Color

Two true-breeding mutant strains of Drosophila have black body color instead of the wild-type gray yellow.When the two strains are crossed,all the F₁ flies have wild-type body color.How can these data be interpreted?

A) Recombination occurred.
B) Complementation occurred.
C) The mutations involved are on two different genes.
D) A new mutation occurred in all the offspring.
E) Both B and C