Your favorite gas station is having a super sale and is selling regular unleaded gasoline at $1.239 per gallon. Using x as the independent variable representing the number of gallons purchased and C as the dependent variable representing the total cost of the fuel, you come up with an equation of C = 1.239 x. You also have the following information listed on the following table. Number of Gallons Purchased (x) 5 10 15 20 Total Cost of the Purchase (C) $6.20 $12.39 $18.59 $24.78 You have only $10 with you. Determine how many gallons you can purchase with this amount. Round to the nearest gallon. a. 8.1 gallons b. 9 gallons c. 7 gallons d. 8 gallons