The following descriptions summarize the fields illustrated in Figure: SNMPv1 Get, GetNext, Response, and Set PDUs Contain the Same Fields:
- PDU type - Specifies the type of PDU transmitted.
- Request ID - Associates SNMP requests with responses.
- Error status - Indicates one of a number of errors and error types. Only the response operation sets this field. Other operations set this field to zero.
- Error index - Associates an error with a particular object instance. Only the response operation sets this field. Other operations set this field to zero.
- Variable bindings - Serves as the data field of the SNMPv1 PDU. Each variable binding associates a particular object instance with its current value (with the exception of Get and GetNext requests, for which the value is ignored).
The Simple Network Management Protocol (SNMP) is an application layer protocol that facilitates the exchange of management information between network devices. It is part of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite. SNMP enables network administrators to manage network performance, find and solve network problems, and plan for network growth.
So ans is B
ref: http://docwiki.cisco.com/wiki/Simple_Network_Management_Protocol