The role of the parasympathetic nervous system in the male sexual response is to promotes relaxation and er_ection.
Option d is correct
While the sympathetic nervous system primarily fuels the fight-or-flight response and drives the initial stages of the male sexual response, the parasympathetic nervous system plays a crucial role in the later stages.
It activates the release of acetylcholine, which promotes relaxation and counterbalances the stimulating effects of the sympathetic system. This helps maintain an ere_ction and facilitates further aro_usal.
The parasympathetic system also stimulates the release of nitric oxide, which dilates blood vessels in the pe_nis, allowing for increased blood flow and maintaining the ere_ction.