Hey there!
Here is your answer:
The proper answer to this question is option C "A dog runs an average of 8mp/h".
Reason:
The sentence A dog runs an average of 8mp/h (option C) is a example of speed because it is telling the average SPEED of a dog which is 8 miles per hour.
Also....
Its not option A because km/h is a distance. Its not option B because its just saying where the rock is located. Its also not option D because its just saying the distance of where Leo lives.
Therefore the answer is option C.
If you need anymore help feel free to ask me!
Hope this helps!
~Nonportrit