Look, read and choose. (看图，选择合适的答句)

A. What's your name?

B. Where are you from?

C. Where is she from?

A. I'm from Canada.

B. I'm a boy.

C. I'm from America.

A. Nice to meet you, too.

B. How are you?

C. Welcome!

男性，40岁，既往体健。吸烟20余年，近2周来咳嗽，痰中带血，1周来左侧胸闷、气短，但无发热和胸痛而应诊。

最简便且有价值的辅助检查项是（）。

A.胸片

B.心电图

C.超声心动图

D.肺通气扫描

E.肺灌注扫描