Task: Question Answering
Input (English): Problem: a certain car uses 12 gallons of gasoline in traveling 120 miles . in order for the car to travel the same distance using 10 gallons of gasoline , by how many miles per gallon must the car ’ s gas mileage be increased ? 
Options: a ) 2 , b ) 4 , c ) 6 , d ) 8 , e ) 10
Output (English): a