_____ can be conducted at any place and time friendly forces are in close proximity to enemy forces.

Close Air Support is a specific military operation that involves providing air strikes in close proximity to friendly forces engaged with the enemy. This form of support is designed to assist ground troops by taking out enemy positions while minimizing the risk of friendly casualties. The term "danger close" refers to situations where friendly forces are in very close range to the enemy, making the coordination of air support crucial to ensure accuracy and safety.

In the context of this question, Close Air Support is the most suitable answer because it is explicitly designed for operations where friendly forces are nearby the enemy. While Close Combat Attack is similar in intention, it typically refers to combat situations that engage enemy forces in close quarters, the most well-known being those carried out by integrated ground and air forces working closely together. Army Attack Aviation refers to helicopter units delivering firepower, and while it can operate in proximity to the enemy, it doesn't convey the same coordinated support as Close Air Support.

Understanding the roles and terminology of these operations is essential, particularly concerning the safety and effectiveness of combat engagements near allied forces.