Defensive Counter Air (DCA) implements which types of missile defense measures?

Defensive Counter Air (DCA) implements both active and passive missile defense measures to protect against airborne threats. Active measures involve the direct engagement of incoming missiles through intercepting projectiles or the use of electronic warfare tactics that disrupt or destroy the enemy's capabilities. These might include surface-to-air missiles or fighter aircraft that actively engage hostile threats.

In contrast, passive measures do not involve direct action against the threats but rather focus on enhancing survivability through various means. These can include camouflage, concealment, and decoys, as well as strategies designed to improve situational awareness and early detection of incoming threats.

The combination of both active and passive measures forms a comprehensive defense strategy capable of adapting to different threats and scenarios in the air domain. This dual approach ensures that a multifaceted defense is in place to minimize risk and enhance security. Other options, while related, do not accurately capture the essence of how DCA operates in missile defense.