A 32-year-old man with a history of multiple endocrine neoplasia type 1 (MEN-1) presents to the emergency department with a 2-month history of episodic severe headaches, profuse diaphoresis, and palpitations. Episodes occur unpredictably, 2-3 times weekly, and last 15-30 minutes. Vital signs show BP 178/108 mmHg, HR 116/min, RR 16/min, temperature 37.1°C. Physical examination reveals no orthostatic hypotension or focal neurologic deficits. A 24-hour urine collection shows elevated metanephrines at 420 nmol/24h (normal <100 nmol/24h). The patient has not taken any sympathomimetic medications or decongestants. Which of the following is the most appropriate next diagnostic step?

1. A)Initiate phentolamine infusion during an acute hypertensive episode to confirm diagnosis
2. B)Perform high-resolution CT imaging of the adrenal glands and abdomen
3. C)Measure plasma free metanephrines after 30 minutes of supine rest in a quiet roomGABARITO
4. D)Proceed directly to surgical consultation for adrenalectomy based on biochemical confirmation
5. E)Obtain a clonidine suppression test to differentiate pheochromocytoma from essential hypertension