High-pressure systems are associated with cool air that sinks and creates outward-flowing winds. Therefore, the correct statement is:
Cool air warms as it sinks and the wind blows outward.
In high-pressure systems, the air in the center is cooler and denser, causing it to sink. As it descends, it compresses and warms. The resulting outward movement of air from the high-pressure center creates the wind associated with these systems.