What event might cause a commander to transition from offense to defense?

A commander might transition from offense to defense in response to achieving a significant victory, as this could indicate that their forces need to consolidate gains, fortify positions, or prepare to repel a counterattack. After a successful offensive operation, resources may be stretched thin, and the need to hold onto newly acquired territory becomes essential. This shift also allows the commander to exploit the advantages earned from the victory, focusing on maintaining control and preparing for future operations rather than further aggressive maneuvers.

The other options present scenarios that do not necessarily prompt an immediate transition to defense. Increased reinforcements typically enhance offensive capabilities, allowing the commander to maintain or amplify their attack. Additional orders may redirect an operation, but do not inherently dictate a defensive posture. Lastly, a change in strategy can lead to various adjustments in tactics, either in offense or defense, but does not automatically necessitate a defensive response.