Final answer:
Vehicles required to have a slow-moving emblem cannot exceed a speed higher than 25 miles per hour.
Step-by-step explanation:
Vehicles required to display a slow-moving emblem are generally not allowed to exceed a certain speed high enough to warrant the use of the emblem. Typically, such vehicles cannot travel faster than 25 miles per hour. Therefore, the correct answer to the student's question is '1) 25 miles per hour.' It's important to note that the speed limit for these vehicles can vary by jurisdiction, so always check local laws for the most accurate information.