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': 'A cardiologist asks for measurement of electromechanical systole and left ventricular ejection time (LVET) and pre ejection period (PEP). The cardiologist is informed by the technician that the carotid transducer is not functioning . Which of the following readings could not be obtained \nSelect and explain. \nA. QS2, B. QS2 and LVET, C. QS2 and PEP, D. LVET and PEP', 'role': 'user'}, {'content': 'Answer: D \nExplanation: If carotid transducer is not functioning we would not be able to measure LVET and PEP.', 'role': 'assistant'}]