What are the two methods used to break contact with an enemy force?

The correct choice encompasses the essential concepts for maintaining operational effectiveness while disengaging from an enemy force. Fire and maneuver refers to a coordinated action where one element provides covering fire while another element moves to safety. This method is vital in allowing a unit to break contact without exposing themselves unnecessarily to enemy fire, effectively minimizing risk during withdrawal.

The mention of the "clock system" relates to the communication strategy often employed in military operations for referencing enemy positions and movements. This method enhances situational awareness among team members and facilitates effective coordination during the maneuver and withdrawal.

In contrast, the other strategies listed do not fully encapsulate the most standardized or tactical approaches typically emphasized in fire team operations when specifically addressing breaking contact. Each of those approaches may have their own merits in different contexts, but they do not align with the core principles of immediate engagement and tactical movement up to the specified context of breaking contact with the enemy.