The correct answer is A) Warn of small targets that are initially detected closer than the outer guard zone. The inner guard zone of an Electronic Plotting Aid (EPA) is designed to detect and provide early warning of small targets that may not be initially picked up by the outer guard zone. This allows the watch officer to have additional time to assess the potential threat and take appropriate action, if necessary, especially in situations where the target may be difficult to detect. The other answer choices are incorrect because: B) is focused on maneuvering situations, C) is related to the preset closest point of approach (CPA) limit, and D) is about the purpose of the overall guard zone system, not the specific inner zone.