In Thomas Hunt Morgan's Experiments, the Ratio of Red-Eyed Flies

In Thomas Hunt Morgan's experiments, the ratio of red-eyed flies to white-eyed flies appeared to follow a simple Mendelian pattern of inheritance. What observation(s) did he make that led to his conclusion that the white-eyed trait was actually not a simple Mendelian trait?

A) He was able to correlate the expression of white eyes to the inheritance of an X chromosome.
B) He saw that only males had white eyes.
C) He observed that the white-eyed trait was recessive.
D) He was able to correlate the expression of white eyes to the inheritance of a Y chromosome because . only F₂ males had white eyes and the trait is recessive.
E) He was able to correlate the expression of white eyes to the inheritance of an X chromosome . because only F₂ males had white eyes and the trait is recessive.