Once a fire is detected the engine should be slowed downOn no account _____.A.the trunking

Once a fire is detected the engine should be slowed downOn no account _____.

A.the trunking should be opened up

B.should the trunking be opened up

C.the trunking should not be opened up

D.should the trunking not be opened up

请帮忙给出正确答案和分析，谢谢！