A 37-year-old male is brought to the emergency room by his wife. Over the past several days, he has complained  of abdominal pain and nausea, which has been associated with occasional vomiting. During the past two days, he  has been much more sleepy than normal. His vital signs are a temperature of 99.0°F, pulse of 113 bpm, and blood  pressure of 91/61 mm Hg. His ACTH is 121 ng/L, and his cortisol is 1 microg/dL. Of the following, what is the  most likely diagnosis?

a. Infarction of the pituitary gland

b. Waterhouse-Friderichsen syndrome

c. Cushing’s disease

d. Congenital adrenal hyperplasia

e. Pheochromocytoma