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
[{'content': "'c' wave of JVP \nSelect and explain. \nA. Occurs during rapid filling phase of cardiac cycle, B. Occurs due to opening of tricuspid valve, C. Occurs due to closure of tricuspid valve into right atrium, D. Occurs at the end of T wave", 'role': 'user'}, {'content': "Answer: C \nExplanation: c' wave of JVP\n\nOccurs due to bulging of tricuspid valve into right atrium\nOccurs during isovolumetric contraction phase\nIn tricuspid regurgitation, v wave merge with c wave.", 'role': 'assistant'}]