First off, we neee to convert the units:
1 miles = 5280 feet
1 hour = 60 minutes
In this case:
60 miles = 5280×60 = 316800 feet
1 hour = 60 minutes
To find the answer, which is the speed,”we divide the length by it's time:

Therefore the answer is C. 5280 ft/min.
Hope it helps!