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: pure milk costs 3.60 per litre . a milkman adds water to 25 litres of pure milk and sells the mixture at 3 per litre . how many litres of water does he add ? 
Options: a ) 2 litres , b ) 5 litres , c ) 7 litres , d ) 11 litres , e ) none of these
[A]: b


[Q]: Problem: the greatest number which on dividing 1657 and 2037 leaves remainders 10 and 7 respectively , is : 
Options: a ) 123 , b ) 1 , c ) 235 , d ) 305 , e ) 505
[A]: b


[Q]: Problem: product of two natural numbers is 3 . then , the sum of reciprocals of their squares is 
Options: a ) 10 / 9 , b ) 1 / 289 , c ) 290 / 90 , d ) 290 / 19 , e ) none of these
[A]:
a