Dynamic stretching in a warm-up is meant to:

Dynamic stretching during a warm-up is specifically designed to prepare the body for physical activity by enhancing flexibility and range of motion in the muscles and joints. This type of stretching involves moving parts of your body through their full range of motion in a controlled manner, which not only helps to loosen the muscles but also increases blood flow and enhances muscle temperature.

By activating the muscles and joints through dynamic movements, you improve their readiness for more strenuous activity, which can enhance overall performance and reduce the risk of injury. Activities such as leg swings, walking lunges, and arm circles exemplify dynamic stretching techniques that accomplish this goal.

The other options do not encapsulate the primary purpose of dynamic stretching: stabilizing the body is more associated with static stretching or strength training techniques, decreasing circulation is contrary to the expected physiological response during a warm-up, and preparing for balance exercises is far too narrow in scope compared to the broader benefits of dynamic stretching as part of a complete warm-up routine.