To determine the movement in the 'Stand at Ease' position, we need to understand the different types of body movements:
In the 'Stand at Ease' position, legs are positioned apart and hands are brought to the sides. Here, when considering the part of the command that involves bringing arms or hands back towards the body (from an extended 'Attention' position), the primary movement is Adduction, as this involves moving the arms from an outward position back towards the body (midline).
Thus, the correct answer is: Adduction