The metric assigned to each network depends on the type of protocol. Some simple protocol, like RIP, treats each network as equals. The ______ of passing through each network is the same; it is one ______ count. So if a packet passes through 10 network to reach the destination, the total cost is 10 hop counts. Other protocols, such as OSPF, allow the administrator to assign a cost for passing through a network based on the type of service required.A ______ through a network can have different costs (metrics). For example, if maximum ______ is the desired type of service, a satellite link has a lower metric than a fiber-optic line. On the other hand, if minimum ______ is the desired type of service, a fiber-optic line has a lower metric than a satellite line. OSPF allow each router to have several routing table based on the required type of service.

A．adaptability
B．scalablity
C．route
D．security

半隐框、隐框玻璃幕墙板块应在洁净、通风的室内打注硅酮结构密封胶，下列环境和相对湿度符合要求的是( )。

A．温度15℃，相对湿度30%

B．温度20℃，相对湿度40%

C．温度25℃，相对湿度50%

D．温度40℃，相对湿度60%