<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 47-year-old man presents to the physicians office with an inability to maintain an erection. He can achieve an erection, but it is brief and decreases soon after the penetration. His erectile dysfunction developed gradually over the past 2 years. He denies decreased libido, depressed mood, or anhedonia. He does not report any chronic conditions. He has a 20-pack-year history of smoking and drinks alcohol occasionally. He weighs 120 kg 264.5 lb, his height is 181 cm 5 ft 11 in, and his waist circumference is 110 cm 43 in. The blood pressure is 14590 mm Hg and the heart rate is 86min. Physical examination is performed including a genitourinary and rectal examination. It reveals no abnormalities besides central obesity. Which of the following laboratory tests is indicated to investigate for the cause of the patients condition?? A: Plasma calcium, B: Fasting serum glucose, C: 24-hour urine cortisol, D: Total serum bilirubin, E: Follicle-stimulating hormone,  <response>: This is a patient with erectile dysfunction that has developed gradually over the past 2 years. Important findings include central obesity, hypertension, and a smoking history. There are no symptoms to suggest hormonal abnormalities or psychological causes. The gradual onset makes vascular causes more likely. Diabetes is a risk factor for vascular disease and can cause erectile dysfunction, so checking a fasting glucose would be appropriate. Calcium, cortisol, bilirubin, and FSH are less likely to reveal the cause.B: Fasting serum glucose 