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': 'The feature of JVP in cardiac tamponade is \nSelect and explain. \nA. Prominent x descent with prominent y descent, B. Prominent x descent with absent y descent, C. Absent x descent with prominent y descent, D. Absent x descent with absent y descent', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]