The ping command is an operational and diagnostic tool used to test network reachability. In the RUCKUS FastIron operating system, such commands are executed from the privileged EXEC mode, which is indicated by the # prompt. The other prompts shown, (config)# and (config-if-...)#, represent global and interface-specific configuration modes, respectively. While in these configuration modes, operational commands like ping can typically be run by prefixing them with the do command (e.g., do ping 1.1.1.1), they cannot be executed directly. The question asks at which prompt the command can be executed, implying direct execution.

A. ICX7150-C12 Router(config-if-mgmt-1)# is the management interface configuration mode. Operational commands cannot be executed directly from this prompt.

B. ICX7150-C12 Router(config)# is the global configuration mode. It is used for system-wide settings, not for executing operational commands directly.

D. ICX7150-C12 Router(config-if-e1000-1/1/1)# is a specific physical interface configuration mode. Operational commands cannot be executed directly from this prompt.

1. RUCKUS FastIron Command Reference, 08.0.95: The documentation for the ping command consistently shows its execution from the privileged EXEC mode. The command syntax examples are presented with the # prompt, such as ICX7150-24P Router# ping 10.20.30.40. This confirms the command's context. (See Chapter: "IP Application Commands", Section: "ping").

2. RUCKUS FastIron Administration Guide, 08.0.95: This guide describes the different Command Line Interface (CLI) modes. It explicitly states that privileged EXEC mode is used for "executing configuration and management commands," which includes diagnostics like ping. In contrast, it defines global configuration mode for making changes that affect the device as a whole. (See Chapter: "Getting Started with the CLI", Section: "CLI command modes").