Which statement about SNMP is true?

A.
SNMP version 2 uses a proxy agent to forward GetNext message to SNMP version 3.

B.
SNMP version 2 supports message integrity to ensure that a packet has not been tampered
with in transit.

C.
Proxy agents were used only in SNMP version 1.

D.
SNMP version 3 supports encryption and SNMP version 2 support authentication.

E.
GetBulk messages are converted to GetNext messages by the proxy agent and are then
forwarded to the SNMP version 1 agent.

Explanation:
Proxy agents:
A SNMPv2 agent can act as a proxy agent on behalf of SNMPv1 managed devices, as follows:
A SNMPv2 NMS issues a command intended for a SNMPv1 agent.
The NMS sends the SNMP message to the SNMPv2 proxy agent.
The proxy agent forwards Get, GetNext, and Set messages to the SNMPv1 agent unchanged.
GetBulk messages are converted by the proxy agent to GetNext messages and then are
forwarded to the SNMPv1 agent.
The proxy agent maps SNMPv1 trap messages to SNMPv2 trap messages and then forwards
them to the NMS.

SNMPv3 provides important security features:[11]
Confidentiality – Encryption of packets to prevent snooping by an unauthorized source.
Integrity – Message integrity to ensure that a packet has not been tampered while in transit
including an optional packet replay protection mechanism.
Authentication – to verify that the message is from a valid source.