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'.
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Question: 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

Answer: c


Question: Problem: 8597 - ? = 7429 - 4358 
Options: a ) 3567 , b ) 6424 , c ) 6835 , d ) 5526 , e ) none of these

Answer: d


Question: Problem: if x and y are integers such that ( x + 1 ) ^ 2 is less than or equal to 16 and ( y - 1 ) ^ 2 is less than 64 , what is the sum of the maximum possible value of xy and the minimum possible value of xy ? 
Options: a ) - 16 , b ) - 10 , c ) 0 , d ) 14 , e ) 16

Answer:
b