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: Consider Input: Problem: of the final grades received by the students in a certain math course , 1 / 5 are a ' s , 1 / 4 are b ' s , 1 / 2 are c ' s , and the remaining 30 grades are d ' s . what is the number of students in the course ? 
Options: a ) 80 , b ) 110 , c ) 160 , d ) 600 , e ) 400

Output: d


Input: Consider Input: Problem: the denominator of a fraction is 6 greater than the numerator . if the numerator and the denominator are increased by 1 , the resulting fraction is equal to 4 â  „ 5 . what is the value of the original fraction ? 
Options: a ) 17 / 23 , b ) 23 / 29 , c ) 29 / 35 , d ) 31 / 37 , e ) 33 / 39

Output: b


Input: Consider Input: Problem: the difference between the place values of two sevens in the numerical 69758472 is 
Options: a ) 0 , b ) 6993 , c ) 699930 , d ) 996330 , e ) none of them


Output: c