Final answer:
The University of Arizona Parking and Transportation Regulations are enforced during classes, weekdays, business hours, and special events.
Step-by-step explanation:
The University of Arizona Parking and Transportation Regulations are enforced during classes, weekdays, and business hours. They may also be enforced during special events. Therefore, the correct answer is option 1) Only when classes are in session, option 2) Only on weekdays, option 3) Only during business hours, and option 4) Only during special events.