At What Point in Cell Division Is a Chromosome Lost

At what point in cell division is a chromosome lost so that, after fertilization with a normal gamete, the result is an embryo with 45, X?
I.an error in anaphase I
II.an error in anaphase II
III.an error of the first postfertilization mitosis
IV.an error in pairing

A) I or II only
B) II or IV only
C) III or IV only
D) I, II, or III only
E) I, II, III, or IV