<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 34-year-old female presents to the emergency room with headache and palpitations. She is sweating profusely and appears tremulous on exam. Vital signs are as follows: HR 120, BP 190110, RR 18, O2 99 on room air, and Temp 37C. Urinary metanephrines and catechols are positive. Which of the following medical regimens is contraindicated as a first-line therapy in this patient?? A: Phenoxybenzamine, B: Nitroprusside, C: Propranolol, D: Labetalol, E: Lisinopril,  <response>: This is a question about the appropriate first-line medical therapy for a patient presenting with symptoms and lab findings consistent with pheochromocytoma. The key findings are headache, palpitations, diaphoresis, tremor, hypertension, and positive metanephrine and catechol levels. Pheochromocytoma is a tumor of the adrenal medulla that secretes excess catecholamines like epinephrine and norepinephrine, leading to paroxysmal hypertension. The contraindicated first-line therapy in pheochromocytoma is a non-selective beta blocker like propranolol. Beta blockers should be avoided as initial therapy because blockade of beta-2 receptors can lead to unopposed alpha receptor stimulation, worsening hypertension. Options like phenoxybenzamine an alpha blocker, nitroprusside, and labetalol an alphabeta blocker are preferred first-line agents to control blood pressure. Lisinopril an ACE inhibitor may be used as adjunctive therapy but is not first-line.C: Propranolol 