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'.

[Q]: Problem: what is the least whole number that should be added to 784839 if it is to be divisible by 10 ? 
Options: a ) 3 , b ) 2 , c ) 1 , d ) 5 , e ) 6
[A]: c


[Q]: Problem: a collection of books went on sale , and 2 / 3 of them were sold for $ 2.25 each . if none of the 40 remaining books were sold , what was the total amount received for the books that were sold ? 
Options: a ) $ 160 , b ) $ 150 , c ) $ 280 , d ) $ 200 , e ) $ 180
[A]: e


[Q]: Problem: if 4 xz + yw = 4 and xw + yz = 8 , what is the value of the expression ( 2 x + y ) ( 2 z + w ) ? 
Options: a ) 22 , b ) 20 , c ) 24 , d ) 26 , e ) 28
[A]:
b