The Ability of Genital End-Bulbs to Cause an Erection Is

The ability of genital end-bulbs to cause an erection is most likely due to their

A) location only in the glans and frenulum.
B) high density in the glans and frenulum.
C) response to chemicals such as nitric acid.
D) ability to trigger a brain response.
E) motor, as opposed to sensory, nerve impulses.