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'.

Ex Input:
Problem: x varies inversely as square of y . given that y = 3 for x = 1 . the value of x for y = 6 will be equal to :
Options: a ) 3 , b ) 6 , c ) 1 / 4 , d ) 1 / 3 , e ) 9

Ex Output:
c

Ex Input:
Problem: a parking garage rents parking spaces for $ 10 per week or $ 25 per month . how much does a person save in a year by renting by the month rather than by the week ?
Options: a ) $ 120 , b ) $ 160 , c ) $ 220 , d ) $ 240 , e ) $ 260

Ex Output:
a

Ex Input:
Problem: each of 3 investments has a 20 % of becoming worthless within a year of purchase , independently of what happens to the other two investments . if simone invests an equal sum v in each of these 3 investments on january 1 , the approximate chance that by the end of the year , she loses no more than 1 / 3 of her original investment is
Options: a ) 90 % , b ) 80 % , c ) 70 % , d ) 60 % , e ) 40 %

Ex Output:
a