问题：
[单选题] The Border Gateway Protocol（BGP）is an interautonomous system（71）protocol.The primary function of a BGP speaking system is to exchange network（在此空作答）information with other BGP system.This network reach
A、secubility
B、reachability
C、capability
D、reliability
参考答案：
B、reachability
● 参考解析
