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: Physiology
There is mutation of gene coding for the ryanodine receptors in malignant hypehermia. Which of the following statements best explains the increased heat production in malignant hypehermia? 
Select and explain. 
A. Increased muscle metabolism by excess of calcium ions, B. Thermic effect of blood, C. Increased sympathetic discharge, D. Mitochondria thermogenesis
A: Increased muscle metabolism by excess of calcium ions
Answer: A: Increased muscle metabolism by excess of calcium ions 
Explanation: A i.e. Increased muscle metabolism by excess of Ca2+ ions