Why Are X-Linked Traits More Commonly Expressed in Males

Multiple Choice

Why are X-linked traits more commonly expressed in males?

A) There is no masking of an affected X allele with a normal X in males.
B) Females must have two copies of the affected allele to display a phenotype.
C) Females may be unknowing carriers and pass on the trait to male progeny.
D) Males only have one X chromosome.
E) All of the above.