In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Ex Input:
Problem: a fruit seller had some oranges . he sells 30 % oranges and still has 420 oranges . how many oranges he had originally ? 
Options: a ) 420 , b ) 600 , c ) 220 , d ) 400 , e ) none of these

Ex Output:
b


Ex Input:
Problem: in a certain math department , students are required to enroll in either calculus or trigonometry , each of which is offered in beginner and advanced courses . the number of students enrolled in trigonometry is 50 % greater than the number of students enrolled in calculus , and 80 % of calculus students are enrolled in the beginner course . if 4 / 5 of students are in the beginner courses , and one student is selected at random , what is the probability that a beginner trigonometry student is selected ? 
Options: a ) 40 % , b ) 44 % , c ) 48 % , d ) 52 % , e ) 56 %

Ex Output:
c


Ex Input:
Problem: what is the rate percent when the simple interest on rs . 800 amount to rs . 144 in 4 years ? 
Options: a ) 5 % , b ) 8 % , c ) 3 % , d ) 4.5 % , e ) 1 %

Ex Output:

d