It is definite that new digital mobile phones have less radiation, but that does not mean________that they should be used without caution.

A．obviously

B．necessarily

C．generally

D．eventually

下列关于报警阀组安装与技术检测共性要求的叙述中，正确的是（）。

A.阀体底边距室内地面高度为0.5m

B.侧边与墙的距离不小于1.2m

C.正面与墙的距离不小于1.2m

D.报警阀组凸出部位之间的距离不小于1.2m