Final answer:
A customer towing a 3,100-pound trailer would need a Class III hitch, as it is suitable for towing trailers between 3,500 and 5,000 pounds and provides a safety margin above the weight of the trailer.
Step-by-step explanation:
The class of trailer towing hitch needed for a customer towing a 3,100-pound trailer would be Class III. Trailer hitch classes are differentiated based on the maximum weight they can safely tow. Here's a quick breakdown:
Considering the trailer's weight is 3,100 pounds, a Class III hitch is the appropriate choice because it is rated for weights exceeding that of the trailer while also providing a safety margin. It is important for safety and legal reasons to choose the correct class of hitch for towing.