136. A 55 year old man comes to the physician with vertigo and disequilibrium while exercise. He says that his symptoms are precipitated by exercising his arms or by raising his arms above his head. He has coronary artery disease and hypertension and he is receiving treatment for that. He has bilateral carotid bruits, rest of the physical exam is normal. What is the diagnosis of this patient ? a. Peripheral artery disease b. Cerebrovascular disease c. Subclavian steal syndrome d. Thromboembolism