Answer:
c.
5:8
Explanation:
The ratio between two values, a and b, is given by:
, or r = a:b.
In this question:
91 kilometers trip.
35 kilometers ran.
The distance left is 91-35 = 56 km.
Ratio between the distance ran and the distance left:
This means that a = 35, b = 56. So

We can simplify both values by 7.

So the correct answer is:
c.
5:8