This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular System, Subject name: Anatomy
The cardiac jelly formed around the heart tube during early development, contributes to the formation of: 
Select and explain. 
A. Pericardium, B. Mesocardium, C. Myocardium, D. Endocardium
D: Endocardium
Answer: D: Endocardium 
Explanation: Ans. is D. The most appropriate answer to this question is actually endocardial cushion.