计算机术语中的“防火墙”：

A．是在网络服务器所在的机房中建立的一栋用于防火的墙

B．用于限制外界对某特定范围内网络的登录与访问

C．不限制其保护范围内主机对外界的访问与登录

D．可以通过在域名服务器中设置参数实现

Oxytocin (Pitocin) is administrated to a client during labor. Which of the following is the most serious adverse effect associated with oxytocin

A．Water intoxication.

B．Tetanic contractions.

C．Elevated blood pressure.

D．Early decelerations of fetal heart rate.