This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
CD 56 is a marker of 
Select and explain. 
A. Intrinsic pathway of apoptosis, B. Extrinsic pathway of apoptosis, C. Necrosis of cell, D. Cellular adaptation
B: Extrinsic pathway of apoptosis
Answer: B: Extrinsic pathway of apoptosis 
Explanation: Ref : Robbins 8/ep29-30,9/e p56