A school has a hurdle track that is 1/5 of a mile long. They are considering extending the track to be 1/4 of a mile long. Note: Figure not drawn to scale.

The committee wants to know the unit rate of length in the longer track per mile of length in the shorter track to make sure they have enough hurdles for the longer track. What is the unit rate?
A.
1/5 of a mile per mile
B.
1 1/5miles per mile
C.
1 1/4miles per mile
D.
1/4 of a mile per mile