SNMP报文中包含三种信息用于身份鉴别，但不包括 (18) 选项。

单项选择题There are several applications called Web (69) that make it easy to access the World Wide Web, two of the most popular being Netscape Navigator and Microsoft’s Internet Explorer.

单项选择题A．在连续5个1之后自动插入一个0B．在连续6个1之后自动插入一个0C．将数据用补码表示D．将数据进行异或处理