Which type of mission provides air interdiction (AI) and close air support (CAS)?

The mission that provides air interdiction (AI) and close air support (CAS) is categorized under counterland operations. Counterland encompasses both air operations targeting land-based forces and supporting ground operations, which is crucial for denying the enemy's ability to use their ground forces effectively.

Air interdiction primarily aims to disrupt or destroy enemy forces and resources on the ground before they can engage friendly forces or before they can move into a position that threatens them. Close air support, on the other hand, involves providing direct support to ground troops engaged in combat, which is critical during battles on the front lines.

This distinction is essential as it helps define how air assets can support ground operations through direct and indirect means, ensuring that ground forces have the necessary air support to achieve their objectives. The focus on land-based engagements in this type of mission illustrates the synergy between air and ground operations, which is why counterland is the correct answer.