What is a cadet required to do when given the position of attention?

When a cadet is given the position of attention, maintaining proper posture is essential, which includes keeping the shoulders back and the chest out. This stance fosters discipline, readiness, and a strong presence, which are critical values in military training and operations.

In the position of attention, having the shoulders back helps align the body, promoting both physical readiness and mental focus. It creates an impression of confidence and respect for command. The chest being out not only contributes to an erect posture but also aids in breathing appropriately, which is important during drills or inspections.

The other options do not adhere to the formal requirements of the position of attention. For example, keeping hands in pockets would command a relaxed posture, which is contrary to the expectations of attentiveness and discipline inherent in military customs. Relaxing and breathing normally, while important for overall well-being, does not convey the readiness that the position of attention demands. Slightly bending the knees may suggest a need for comfort, but the position requires being upright and still. Thus, the emphasis on keeping shoulders back and chest out is what makes this option the correct and appropriate choice.