Which type of kill indicates that a vehicle is no longer capable of combat operations?

A combined firepower mobility kill is the correct answer because it indicates that a vehicle has been rendered incapable of performing its primary mission due to both a loss of mobility and a loss of its combat effectiveness. In military terminology, this type of kill signifies that the vehicle not only cannot move but also has had its weapon systems damaged or destroyed, thus making it unable to engage in combat operations effectively.

Other types of kills, such as mobility kills, refer specifically to the vehicle's inability to move, while firepower kills indicate that the vehicle cannot engage with its weapons. A catastrophic kill typically suggests complete destruction of the vehicle, rendering it unusable in any capacity. However, a combined firepower mobility kill specifically highlights the dual failures in both movement and combat capabilities, which is crucial for understanding the vehicle's operational status on the battlefield.