One week, Kerry travels 125 miles and uses 5 gallons of gasoline. The next week, she travels 175 miles and uses 7 gallons of gasoline. Which best describes the function that can be used to represent m, the number of miles traveled, and g, the number of gallons used?

A. direct variation; m = kg
B. direct variation; gm = k
C. inverse variation;
D. inverse variation;