What kind of modifications are included in signature reduction?

Signature reduction refers to techniques and modifications aimed at decreasing the likelihood of detection by radar and other targeting systems. This can involve altering the shape, materials, or operational tactics of an aircraft or system to mitigate its radar cross-section or thermal signatures. By minimizing the visibility to targeting systems, a platform can operate more effectively in hostile environments without being easily detected, thus enhancing survivability.

While the other options might contribute to overall operational effectiveness, they do not specifically pertain to the concept of signature reduction. Enhancements to speed, strengthening armament, and improving communication systems focus on performance and combat capabilities rather than reducing detectable signatures. Thus, minimizing visibility to targeting systems is the primary focus of signature reduction techniques, making it the correct response.