How can units ensure they remain combat-ready as per FM 7-1?

The correct choice emphasizes the importance of continuous and relevant training exercises in maintaining combat readiness. According to FM 7-1, units must engage in rigorous and realistic training activities to ensure soldiers are proficient in their tasks and familiar with the operational environment. This approach not only reinforces skills but also builds cohesion and adaptability within the unit.

Regular comprehensive training exercises provide soldiers with opportunities to practice and refine their skills in a controlled environment, preparing them for real-world scenarios. Such training includes not only individual soldier tasks but also collective unit operations, ensuring that all members are capable of functioning effectively as a team during combat situations. This level of preparedness is crucial for operational success and mission accomplishment.

The other approaches mentioned would not sufficiently prepare units for combat. Sporadic training sessions may lead to gaps in proficiency, while restricting training to only experienced soldiers would hinder the skill development of newer or less experienced members. Additionally, focusing solely on theoretical knowledge neglects the practical application of skills necessary for real-world combat scenarios. Thus, regular and comprehensive training is essential for sustaining a unit's combat readiness as per the guidelines of FM 7-1.