Answer:
Option 2 - 1 over 8 hour per mile.
Explanation:
Given : A biker traveled 24 miles in 3 hours. A unit rate to describe this would be 8 miles per hour.
To find : What is another unit rate in this situation?
Solution :
A biker traveled 24 miles in 3 hours.
A unit rate to describe this would be 8 miles per hour.
The another unit rate is just invert the first one.
i.e.

Which means it take
to travel 1 mile.
Therefore, The another unit rate in this situation is 1 over 8 hour per mile.
Hence, Option 2 is correct.