Which of the following incorporates improvements on the original SNMP standard, SNMPv1? (Choose all that apply)

A.
SNMPv2

B.
SNMPv3

C.
DMI

D.
All of the above

Explanation:
SNMPv2, SNMPv3, and DMI all improve on the original SNMP standard. DMI was originally designed as a replacement of the initial SNMP standard. The two enhancements to SNMPv1, namely SNMPv2 and SNMPv3 include enhancements to the earlier SNMP standard.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 424-427.