Final answer:
The average speed of your teacher during the marathon is 5.24 mph.
Step-by-step explanation:
To calculate the average speed of your teacher during the marathon, divide the total distance by the total time taken. Your teacher ran 26.2 miles in 5 hours, so the average speed is 26.2 miles / 5 hours = 5.24 mph.
In this case, the correct option is a. 5.24 mph.