诊断支气管扩张首选的检查是（）。

A.胸部X线片

B.胸部高分辨CT

C.支气管造影

D.胸部超声

E.胸部磁共振

For which of the following securities is estimating the future cash flows least difficult（）

A. 5-year, 6% bond with two years of call protection.

B. 3-year note with a coupon of Libor + 100 basis points.

C. 8% preferred stock with mandatory redemption in five years.