This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Muscular weakness due to deficiency of magnesium is enhanced by presence of - 
Select and explain. 
A. Hyperkalemia, B. Metabolic alkalosis, C. Metabolic acidosis, D. Hypernatremia
C: Metabolic acidosis
Answer: C: Metabolic acidosis 
Explanation: None