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: Physiology
Protein responsible for preventing overstretching of cardiac muscle 
Select and explain. 
A. Actinin, B. Nebulin, C. Myomesin, D. Titin
D: Titin
Answer: D: Titin 
Explanation: Titin is responsible for elasticity of muscle and preventing overstretching of cardiac muscle.