This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
Digoxin toxicity is aggravated by 
Select and explain. 
A. Hyperkalemia, B. Hyperkalemia, C. Hypermagnesemia, D. Hypocalcemia
A: Hyperkalemia
Answer: A: Hyperkalemia 
Explanation: Ref-KDT 6/e p499 Oxygen toxicity is a agravated by Hypokalemia and hypercalcemia