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'.

Example Input: Problem: a is the hundreds digit of the 3 digit integer x , b is the tens digit of x , and c is the units digit of x . 4 a = 2 b = c , and a > 0 . what is the difference between the two greatest possible values of x ? tip : dont stop till you have exhausted all answer choices to arrive at the correct one . 
Options: a ) 124 , b ) 297 , c ) 394 , d ) 421 , e ) 842
Example Output: a

Example Input: Problem: if a number x is 10 % less than another number y and y is 10 % more than 125 , then x is equal to 
Options: a ) 143 , b ) 150 , c ) 123.75 , d ) 140.55 , e ) none
Example Output: c

Example Input: Problem: a boy perform 5 times a reaction and his reading are 2 , 2.1 , 2 , 2.2 but unfortunately 5 th reading clearly not visible because a drop of chemical fall onto it . but luckily he have mean of all reading which is 2 . please help him in finding 5 th reading . 
Options: a ) 2 , b ) 1.7 , c ) 1.9 , d ) 1.8 , e ) 2.1
Example Output:
b