When Thomas Hunt Morgan Crossed His Red-Eyed F₁ Generation Flies

When Thomas Hunt Morgan crossed his red-eyed F₁ generation flies to each other, the F₂ generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?

A) The gene involved is located on the Y chromosome.
B) The gene involved is located on the X chromosome.
C) The gene involved is located on an autosome, but only in males.
D) Other male-specific factors influence eye color in flies.