Both parents and teachers work hard at either preventing failure or protecting the children from the knowledge_______ they have failed.

A．where

B．why

C．which

D．that

细水雾灭火系统的基本设计参数应根据细水雾灭火系统的特性和防护区的具体情况确定。喷头的最低设计工作压力不应小于（）MPa。

A.1.00

B.1.10

C.1.20

D.1.50