What is the main role of the SM-2 and SM-6 Standard Missile?

The primary function of the SM-2 and SM-6 Standard Missiles is to provide surface-to-air defense capabilities. Both missiles are designed to engage and destroy incoming aerial threats, such as enemy aircraft and missiles, thereby protecting naval vessels and the surrounding area from air attacks.

The SM-2 missile is a versatile weapon that can counter aircraft and anti-ship missiles, while the SM-6 extends these capabilities to include a broader array of targets, such as cruise missiles and even some ballistic missile threats. The development of these missiles represents a significant advancement in naval air defense systems, enhancing the overall effectiveness and survivability of naval forces in combat situations.

The other options do not accurately reflect the primary roles of these missiles. For instance, naval surface warfare encompasses a broader range of activities and systems, while underwater target engagement and close air support for ground troops are completely different operational focuses that are not what the SM-2 and SM-6 were specifically designed for. Thus, the correct choice emphasizes the primary surface-to-air defense role of these missiles.