单选题 A client with myocardial infarction and cardiogenic shock is placed in an intra-aortic balloon pump (IABP). If the device is functioning properly, the balloon inflates when the
A. triseupid valve is closed.
B. pulmonic valve is open.
C. aortic valve is closed.
D. mitral valve is closed.

【正确答案】 C

【答案解析】An IABP inflates during diastole when the tricuspid and mitral valves are open and the aortic and pulmonic valves are closed.