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: Biochemistry
Serum marker to return to normal level, last in myocardial infarction is: 
Select and explain. 
A. Lactate dehydrogenase, B. Creatine phosphokinase, C. Aspaate transmainase, D. Myoglobin
A: Lactate dehydrogenase
Answer: A: Lactate dehydrogenase 
Explanation: Enzymes in MILDH is the last enzyme to rise (3-4 days) and also the last enzyme to return to normal level in MI (10-15 days)CPK returns to normal by 2-3 daysAST/ SCOT returns to normal by 4-5 daysMyoglobin returns to normal by 20-25 hours