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: Medicine
'C' wave in JVP is due to - 
Select and explain. 
A. Atrial contraction, B. Tricuspid valve bulging into right atrium, C. Right atrial filling, D. Rapid ventricular filling
B: Tricuspid valve bulging into right atrium
Answer: B: Tricuspid valve bulging into right atrium 
Explanation: None