This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Adrenal Gland, Subject name: Medicine
Which is least likely to be elevated in patients with a pheochromocytoma? 
Select and explain. 
A. Systemic aerial diastolic pressure, B. Systemic aerial systolic pressure, C. Serum norepinephrine, D. Intravascular volume
D: Intravascular volume
Answer: D: Intravascular volume 
Explanation: Pheochromocytoma is producing Nor epinephrine & Epinephrine which increases the systolic and diastolic pressure. * Also Nor epinephrine would be higher D/T extreme vasoconstriction the intravascular volume of the patient will be significantly reduced and not elevated.