If the trailer is in excess of ____________ lbs, what must be the stopping distance within _________ at _________ mph?

The correct answer reflects critical safety standards related to the stopping distance of a trailer based on its weight. In this case, if the trailer exceeds 3,000 lbs, it is required that the stopping distance be within 50 feet when traveling at 20 mph.

These specifications are grounded in regulatory guidelines that ensure vehicles, especially those that tow trailers, can stop safely within a certain distance to avoid accidents. The stopping distance is influenced by various factors, including the weight of the trailer, the speed of the vehicle, and the road conditions.

By establishing a requirement of 50 feet at 20 mph for trailers over 3,000 lbs, safety is prioritized in situations where quick stops may be necessary to prevent collisions or loss of control. This standard helps ensure that drivers operating heavier trailers are equipped with knowledge about their vehicle's stopping capabilities, making everyone on the road safer.

In contrast, the other options specify different weight and distance requirements that do not align with the established regulations for trailers, which lessens their relevance in this context. Therefore, the specifications in the correct answer accurately reflect the necessary stopping distances for larger trailers.