Instructions: In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Input: Problem: a solution is 90 % glycerin . if there are 4 gallons of the solution , how much water , in gallons must be addded to make a 75 % glycerin solution
Options: a ) 1.8 , b ) 1.4 , c ) 1.2 , d ) 1.0 , e ) 0.8
Output:
e