Which step is important to take when implementing secure network management?

A.
Implement in-band management whenever possible.

B.
Implement telnet for encrypted device management access.

C.
Implement SNMP with read/write access for troubleshooting purposes.

D.
Synchronize clocks on hosts and devices.

E.
Implement management plane protection using routing protocol authentication.

Explanation:
http://www.cisco.com/en/US/tech/tk869/tk769/technologies_white_paper09186a0080117070.shtml
Background Information
Network time synchronization, to the degree required for modern performance analysis, is an
essential exercise. Depending on the business models, and the services being provided, the
characterization of network performance can be considered an important competitive service
differentiator. In these cases, great expense may be incurred deploying network management
systems and directing engineering resources towards analyzing the collected performance data.
However, if proper attention is not given to the often-overlooked principle of time synchronization,
those efforts may be rendered useless.