Final answer:
The question pertains to Health education, especially road safety, and it is generally taught in Middle School. A school bus should maintain a following distance of at least 4 seconds to ensure safety.
Step-by-step explanation:
The subject of this question is Health, and it pertains to safe following distances when driving, which is typically taught as part of safety education in Middle School. The proper following distance for a school bus should be at least 4 seconds behind the vehicle in front. This allows the driver ample time to react to any sudden stops or changes in traffic conditions. The 4-second rule is considered a safe guideline to provide enough stopping distance for large vehicles such as buses, which require more time to stop due to their size and weight compared to standard passenger vehicles.