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'.

[EX Q]: Problem: if a and b are the roots of the equation x 2 - 9 x + 20 = 0 , find the value of a 2 + b 2 + ab ? 
Options: a ) 57 , b ) 59 , c ) 61 , d ) 63 , e ) 65
[EX A]: c

[EX Q]: Problem: 1257 1275 1527 . . . . . . . . . . . . . . . . + 7521 the addition problem above shows 4 of the 24 different integers that can be formed by using each of the digits 1 , 25 and 7 exactly once in each integer . what is the sum t of the 24 integers ? 
Options: a ) 26996 , b ) 44406 , c ) 60444 , d ) 66660 , e ) 99990
[EX A]: e

[EX Q]: Problem: how many integers between 500 and 1000 are there such that their unit digit is even ? 
Options: a ) 250 , b ) 150 , c ) 500 , d ) 100 , e ) 200
[EX A]:
a