戊型肝炎主要由（）

A．血液传播 

B．飞沫传播 

C．唾液传播 

D．食物传播 

E．蚊虫传播

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.