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
Serum Creatine PhosphoKinase-3 (CPK-3) is elevated in- 
Select and explain. 
A. Muscular dystrophy, B. Myocardial infarction, C. Alcoholic cirrhosis, D. Brain tumours
A: Muscular dystrophy
Answer: A: Muscular dystrophy 
Explanation: Musculardystrophy CreatineKinase(CK)or CreatinePhosphokinase(CPK)catalysestheinterconversionof phosphocreatineto creatine. CPKexistsasthreeisoenzymes.Eachisoenzymeisa dimercomposedoftwosubunits- M(muscle)orB (Brain)orboth Isoenzyme SubUnit Tissueoforigin CPK1 BB Brain CPK2 MB Hea CPK3 MM SkeletalMuscle