At which prompt can the ping command be executed?

Understanding CLI Levels:

The ping command is used to test connectivity to other devices by sending ICMP echo requests.

It can only be executed from the privileged EXEC mode, which is indicated by the Router# prompt.

Why Other Prompts Don't Work:

A. Router(config-if-mgmt-1)#: This is the interface configuration mode for the management port and does not allow execution of diagnostic commands like ping.

B. Router(config)#: This is the global configuration mode, which is used to configure the switch but does not support diagnostic commands.

D. Router(config-if-e1000-1/1/1)#: This is the interface configuration mode for Ethernet 1/1/1, which also does not allow execution of ping.

References:

RUCKUS ICX CLI Guide: RUCKUS Documentation