Jenny was interested in studying how much gas a car uses at different speeds. Jenny did one test with her mother's car and found that it used about 3 percent more gas when speed increased by 5 miles per hour.

How can Jenny make the results of her investigation more reliable?

A. redo the steps of the experiment in a different order
B. communicate her results immediately after the one test
C. repeat the investigation several times
D. avoid recording any data during the experiment