<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 55-year-old man comes to the physician because of difficulties achieving an erection for the past year. A medication is prescribed that inhibits cyclic GMP phosphodiesterase type 5. Which of the following is the most likely site of action of the prescribed drug?? A: Corpus cavernosum, B: Prostate smooth muscle, C: Corpus spongiosum, D: Pelvic splanchnic nerves, E: Pudendal nerve,  <response>: This is a question about erectile dysfunction ED in a 55-year-old man. The medication prescribed inhibits phosphodiesterase type 5 PDE5, which breaks down cyclic GMP. Cyclic GMP is important for smooth muscle relaxation and vasodilation in the penis to allow erection. The corpus cavernosum in the penis fills with blood during erection. Therefore, the medication likely acts in the corpus cavernosum to inhibit PDE5, increase cGMP levels, and promote smooth muscle relaxation and vasodilation for erection. The other options are less directly involved in erection.A: Corpus cavernosum 