Guided missiles have four basic parts. Which of the following is one of them?

One of the fundamental components of guided missiles is the warhead. The warhead is the part of the missile designed to carry explosive or destructive payloads towards a target. Its primary purpose is to deliver damage upon impact, and it plays a critical role in determining the effectiveness of the missile in combat scenarios.

The warhead can vary in type depending on the missile's intended use, ranging from conventional explosives to nuclear payloads. This component is essential because, without it, the missile would not fulfill its primary function as a weapon.

While the other options mentioned, such as a navigation console, defensive system, and launch pad, are related to the overall missile system and its operational capabilities, they do not constitute one of the core parts that make up the missile itself. The navigation console is used for guidance, the defensive system would be for protection, and the launch pad serves as the platform from which the missile is launched, but none of these are considered integral parts of the missile as defined in this context.