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: Pathology
Which protein is defective in Becker muscular dystrophy? 
Select and explain. 
A. Dystrophin, B. Actinin, C. Myotilin, D. Emerin
A: Dystrophin
Answer: A: Dystrophin 
Explanation: In both Duchenne and Becker's gene encoding for Dystrophin is defective.
In Duchenne - Dystrophin is completely absent.
In Beckers - Dystrophin is decreased.