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: boys and girls in a class are writing letters . there are twice as many girls as boys in the class , and each girl writes 3 more letters than each boy . if boys write 24 of the 90 total letters written by the class , how many letters does each boy write ? 
Options: a ) 3 , b ) 4 , c ) 6 , d ) 8 , e ) 12
Example Output: d

Example Input: Problem: if | 5 x - 5 | = 150 , what is the sum of all the possible values of x ? 
Options: a ) 2 , b ) - 2 , c ) 6 , d ) - 3 , e ) 5
Example Output: a

Example Input: Problem: one - tenth of the students at a nursery school are 4 years old or older . if 20 students have not yet reached their third birthday , and a total of 25 students are not between 3 years old and 4 years old , how many children are in the nursery school ? 
Options: a ) 51 , b ) 20 , c ) 40 , d ) 50 , e ) 55
Example Output:
d