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: there were 35 students in a hostel . due to the admission of 7 new students , he expenses of the mess were increased by rs . 42 per day while the average expenditure per head diminished by rs 1 . what was the original expenditure of the mess ? 
Options: a ) 125 , b ) 321 , c ) 561 , d ) 852 , e ) 420
Example Output: e

Example Input: Problem: the toll for crossing a certain bridge is $ 0.75 each crossing . drivers who frequently use the bridge may instead purchase a sticker each month for $ 11.00 and then pay only $ 0.30 each crossing during that month . if a particular driver will cross the bridge twice on each of x days next month and will not cross the bridge on any other day , what is the least value of x for which this driver can save money by using the sticker ? 
Options: a ) 14 , b ) 15 , c ) 16 , d ) 28 , e ) 29
Example Output: e

Example Input: Problem: there are 6 chess amateurs playing in villa ' s chess club tournament . if each chess amateur plays with exactly 15 other amateurs , what is the total number of chess games possible to be played in the tournament ? 
Options: a ) 10 , b ) 20 , c ) 45 , d ) 60 , e ) 120
Example Output:
c