Before filling the car with gas, the odometer reading was 6,967 miles. The next time the car was filled with gas, the odometer reading was 7,326 mi. The amount of gas needed to refill the tank was 17.7 gallons. What is the approximate miles per gallon to the nearest whole number?
A. 10 mpg
B. 18 mpg
C. 20 mpg
D. 36 mpg