Q. A 52-year-old Caucasian male presents to the emergency department with complaints of muscle weakness, muscle cramps, and fatigue for the last 5 days. Patient’s medical history includes hypertension, and diabetes. He does not smoke or use illicit drugs but he has a history of excessive alcohol consumption. His chronic medications include metformin, losartan, metoprolol, and furosemide, which he just started 3 weeks back at 40 mg per day. He is also prescribed a single dose of insulin at night but he is poorly compliant with his insulin therapy and often misses his dose. His temperature is 37.27? (99.1 ?) and BP is 98/61 mmHg. Random blood glucose is 195 mg/dL. His ECG reveals prominent U waves following T waves in leads V2 to V4. Which one of the following drugs is most likely responsible for the ECG changes?