Final answer:
The slave mode of a seeker refers to when the system locks onto a target and maintains tracking, following the target as it moves.
Step-by-step explanation:
When referring to the slave mode of a seeker, typically in the context of guided missile technology, it usually means the system is designed to lock onto a target and maintain tracking or following it regardless of the movement of the target. This mode contrasts with a scanning mode, where a wider area is continuously monitored for potential targets, and is also distinct from a mode that would focus on ignoring decoys to maintain a lock on the primary target. Therefore, the correct description of the slave mode of a seeker is option B) Locks onto the target and follows it.