What type of warfare focuses on wearing down the enemy through constant attacks and resource depletion?

The correct answer is the war of attrition, which describes a military strategy focused on wearing down an adversary through continuous losses in personnel and material. The goal is to weaken the enemy's capacity to sustain the fight, effectively depleting their resources and morale over time. This type of warfare often involves sustained engagements that do not aim for decisive victories in single battles but instead focus on exhausting the opponent.

In contrast, guerrilla warfare involves smaller, irregular forces using ambushes and hit-and-run tactics rather than prolonged engagements. Conventional warfare typically refers to the direct and organized military operations between established armies using conventional weaponry and tactics. Psychological warfare aims to undermine the enemy's will to fight or disrupt their plans through propaganda or psychological tactics, rather than through physical attrition. Therefore, the strategy of attrition distinctly emphasizes the long-term depletion of the enemy's strength, making it the correct answer to the question.