深度为15m的人工挖孔桩工程，（）。

A.不需要编制专项方案也不需要专家论证

B.不需要编制专项方案但需要专家论证

C.要编制专项方案并需要专家论证

D.要编制专项方案，但不需要专家论证

You can indicate that your vessel is in distress by（）.

A.displaying a large red flag

B.displaying three black balls in a vertical line

C.sounding four or more short rapid blasts on the whistle

D.continuously sounding the fog whistle