Why Is It a Good Idea to Use STRs on Y

Multiple Choice

Why is it a good idea to use STRs on Y chromosomes for ancestry instead of STRs on X chromosomes?

A) The Y chromosome is passed on to every generation no matter what.
B) The X chromosome is passed on to every generation no matter what.
C) The X chromosome undergoes crossing over;the Y does not.
D) The Y chromosome undergoes crossing over;the X does not.
E) There are more available STRs on the Y chromosome than on the X chromosome