In Margaret Bastock's Research Examining the Courtship Behavior of Wild

In Margaret Bastock's research examining the courtship behavior of wild type and "yellow" forms of fruit flies she interbred wild type and "yellow" flies to create inbred flies. What was the purpose of this?

A) To create populations of flies that were very similar except for the "yellow" gene
B) To control for environmental conditions during rearing
C) To create populations of flies with the same courtship behavior
D) To control for the age of the flies
E) To control for the mating success of males