C
Below is a question with multiple-choice answers. Choose the correct option based on your reasoning.

### Question:
As Archie walks to the park, he wonders which route would be faster. He decides to walk to the park using different routes and times how long it takes. Which should he do to make his comparison fair?

### Choices:
A. walk to different parts of the park each day
B. walk with a different friend each day
C. walk at the same speed each day
D. walk at the same time of the day

### Answer:
