An 80-year old male with non-obstructive coronary artery disease, diabetes mellitus type 2, and hypertension presents after a fall he had at home about five hours ago. He felt well this morning. After a light breakfast, he read the newspaper at the kitchen table. When he stood up, he felt lightheaded and fell to the floor. His daughter, who lives with him, heard the thud and found him on the floor. He was orientated to person, place, and time when found by his daughter. He denied having any urinary or stool incontinence. He also has not had fevers, palpitations, abdominal discomfort, hematuria, or dysuria. As he was complaining of left hip pain, she brought him into the emergency room for evaluation. He has been prescribed aspirin, metoprolol, enalapril, amlodipine, and metformin, all of which he took this morning. The enalapril was recently added to his regimen. On exam, vitals were as follows: temperature is 37.6 C (99.7 F), pulse is 60 beats/minute, and blood pressure is 110/70 mmHg. You find a pleasant male who appears his stated age and is in no distress. His exam, including the neurological exam, is unremarkable except for ecchymoses over the left hip. He scores a 29 on the mini-mental state examination (MMSE). He is unable to complete a "Get Up and Go" test due to pain in his left hip. Initial tests show a finger stick glucose of 220 mg/dL, sodium 135 mmol/L, creatinine 1.0 mg/dL, white blood cell count 9,000 cells/mL, hemoglobin 14 g/dL, and troponin I 0.01 ng/mL. A urinalysis showed 4+ bacteria with no leukocyte esterase or nitrites. An electrocardiogram (ECG) showed a normal sinus rhythm with significant Q waves in leads II, III, and avF. A non-contrast computed tomography (CT) of the head shows no structural lesions. A pelvic radiograph and magnetic resonance imaging (MRI) of the pelvis both show no evidence of fracture. What is the most likely contributor to his fall? A. Acute coronary syndrome B. Hypoglycemia C. Medications D. Seizure disorder E. Urinary tract infection