在车站、货场或专用线内，专为内部作业使用，不直接贯通道路的平面交叉设备是( )。

A.平过道

B.人行过道

C.专用通道

D.道口

Of the following signs and symptoms of bowel obstruction, which is related primarily to small bowel obstruction rather than large bowel obstruction()

A. Profuse vomiting.

B. Cramping abdominal pain.

C. Abdominal distention.

D. High-pitched bowel sounds above the obstruction.