Which of the following is a reason for conducting defensive operations?

Conducting defensive operations primarily aims to deny the enemy vital areas, which is crucial for maintaining tactical and strategic advantages in military engagements. Defensive operations are designed to protect one's own forces and territory while hindering the enemy's movements and capabilities. By denying the enemy access to important locations, such as key terrain, logistics hubs, or urban centers, a defense can significantly impact the enemy’s operational effectiveness and overall mission success.

For instance, if forces successfully defend a strategic location, it can prevent the enemy from gaining vital resources or establishing a foothold that would threaten further advances. This defensive posture often involves fortifications, tactical positioning, and the employment of various units to create a stalemate or slow the enemy's momentum.

Other options, while related to military operations, do not align with the primary aim of defensive operations. Aerial assaults focus on offensive capabilities rather than defense. Establishing new supply routes is more about logistical support and mobility rather than directly impacting enemy capabilities. Training new soldiers pertains to preparedness and capacity building, which is not the focus of immediate defensive actions.