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: Surgery
A 48 year-old woman underwent subtotal thyroidectomy. She has a vague family history of malignant hypehermia. She develops agitation, restlessness, fever, tremor, shivering, and tachypnea. Thyrotoxic crises can be best distinguished from malignant hypehermia by estimating - 
Select and explain. 
A. Temperature variation, B. Increased CPK levels, C. LDH, D. Muscular rigidity
B: Increased CPK levels
Answer: B: Increased CPK levels 
Explanation: Ans. is 'b' i.e., Increased CPK levels