Women have sex chromosomes of XX, and men have sex chromosomes of XY.

Which of a man's grandparents could not be the source of any of the genes on his Y-chromosome?

A. Father's Mother.

B. Mother's Father.

C. Father's Father.

D. Mother's Mother, Mother's Father, and Father's Mother.

The Y chromosome is inherited solely from father to son in each generation.

E. Mother's Mother.