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

Multiple Choice

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