What does a Marine demonstrate by excelling in the CFT?

Excelling in the Combat Fitness Test (CFT) demonstrates a Marine's ability to perform effectively in combat conditions. The CFT is designed specifically to assess physical fitness in areas that are essential for combat readiness. It evaluates strength, endurance, and other physical capabilities that are critical in real-life combat situations. By performing well in the CFT, a Marine showcases their preparedness to handle the physical demands they may face in stressful environments, reinforcing their operational effectiveness in fulfilling their duties.

The other options, while they highlight different aspects of physical fitness and military training, do not align with the primary purpose of the CFT. Recreational sports, tactical understanding, and injury resistance are important aspects of a Marine's overall training and readiness but are not the direct focus of the CFT. The test specifically targets combat-related fitness, making option A the most relevant choice.