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
What does 'C' Wave in JVP indicate? 
Select and explain. 
A. Atrial contraction, B. Rapid Right ventricular filling, C. Atrial filling with the tricuspid valve closed, D. Bulging of the tricuspid valve into the right atrium
D: Bulging of the tricuspid valve into the right atrium
Answer: D: Bulging of the tricuspid valve into the right atrium 
Explanation: A, C and V waves of JVP occur secondary to pressure changes in the atria which are transmitted to the great veins. The c wave is the transmitted manifestation of the rise in atrial pressure produced by the bulging of the tricuspid valve into the atria during isovolumetric ventricular contraction. Ref: Ganong's Review of Medical Physiology, 23rd Edition, Chapter 31