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: the sum of all the digits of the integers from 18 to 21 inclusive is 24 ( 1 + 8 + 1 + 9 + 2 + 0 + 2 + 1 = 24 ) . what is the sum t of all the digits of the integers from 0 to 99 inclusive ? 
Options: a ) 450 , b ) 810 , c ) 900 , d ) 1000 , e ) 1100
Example Output: c

Example Input: Problem: on a race track a maximum of 5 horses can race together at a time . there are a total of 25 horses . there is no way of timing the races . what is the minimum number y of races we need to conduct to get the top 3 fastest horses ? 
Options: a ) 5 , b ) 7 , c ) 8 , d ) 10 , e ) 11
Example Output: b

Example Input: Problem: there are 9 players in a chess group , and each player plays each of the others once . given that each game is played by two players , how many total games will be played ? 
Options: a ) 10 , b ) 30 , c ) 36 , d ) 60 , e ) 90
Example Output:
c