Which command copies the startup configuration into the running configuration?

• A. copy running-config startup-config
• B. copy startup-config running-config
• C. copy flash:config startup-config
• D. copy startup-config startup-config

Answer: (B)

This question tests how Cisco IOS handles the two configuration stores: the running configuration in RAM and the startup configuration in NVRAM. The startup configuration is what the device loads at boot, while the running configuration is the active set of settings currently in use.

Copying startup-config into running-config applies the saved, boot-time configuration to the active running configuration right away, without needing to reboot. This is useful when you want to revert the device to a previously saved state or restore known-good settings exactly as they were saved in startup-config.

In practice, you use the command with startup-config as the source and running-config as the destination. The effect is that the current active configuration becomes identical to what’s stored in startup-config. The other options either save the current running config back to startup-config, attempt to copy from a different location, or copy a config to itself, which aren’t what this question is asking.