有人认为CH₂=CH₂与Br₂的加成反应，实质是Br₂先断裂为Br⁺和Br^-，然后Br⁺首先与CH₂=CH一端碳原子结合，第二步才是Br^-与另一端碳原子结合．根据该观点如果让CH₂=CH₂与Br₂在盛有NaCl和NaI的水溶液中反应，则得到的有机物不可能是（　　）

A．BrCH₂CH₂Br

B．ClCH₂CH₂Cl

C．BrCH₂CH₂I

D．BrCH₂CH₂Cl

The metric assigned to each network depends on the type of protocol. Some simple protocol, like RIP, treats each network as equals. The (91) of passing through each network is the same; it is one (92) 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 (93) through a network can have different costs (metrics). For example, if maximum (94) is the desired type of service, a satellite link has a lower metric than a fiber-optic line. On the other hand, if minimum (95) 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.

（91）是（）

A.number

B.connection

C.diagram

D.cost