正常心脏左室射血分数（EF)值应为A．EF>40%.B．EF>60%.C．EF>70%.D．EF>80%.E．EF>50%.

正常心脏左室射血分数(EF)值应为

A．EF>40%.

B．EF>60%.

C．EF>70%.

D．EF>80%.

E．EF>50%.

请帮忙给出正确答案和分析，谢谢！