A Man Is Paralyzed Below the Waist Due to an Injury

A man is paralyzed below the waist due to an injury that fully severed his spinal cord. Can this man experience an erection?

A) Yes, but only if the penis is physically stimulated.
B) Yes, but only if he has sexual thoughts or sees something stimulating.
C) Yes, but the erection will be controlled by voluntary, rather than autonomic, nerves.
D) No, because the brain is necessary for an erection to occur.
E) No, because the reflex must travel through both the brain and spinal cord.