This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
Which one of the following molecules serve as the earliest marker in myocardial infarction 
Select and explain. 
A. Myoglobin, B. Troponin, C. HbA2, D. CK MB
A: Myoglobin
Answer: A: Myoglobin 
Explanation: Myoglobin is found in cardiac and skeletal muscle. It is released more rapidly from infarcted myocardium than troponin and CK-MB and may be detected as early as two hours after an acute myocardial infarction. Ref: Biochemistry by U. Satyanarayana 3rd edition Pgno : 107-112