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: if ( a - b - c + d = 13 ) and ( a + b - c - d = 9 ) , what is the value of ( b - d ) ^ 2 ? 
Options: a ) 4 . , b ) 8 . , c ) 12 . , d ) 16 . , e ) 64 .
[A]: a


[Q]: Problem: in 1990 the budgets for projects q and v were $ 500,000 and $ 780,000 , respectively . in each of the next 10 years , the budget for q was increased by $ 30,000 and the budget for v was decreased by $ 10,000 . in which year was the budget for q equal to the budget for v ? 
Options: a ) 1992 , b ) 1993 , c ) 1994 , d ) 1995 , e ) 1997
[A]: e


[Q]: Problem: total 60 cows 20 cow gives each 2 liter milk 20 cow gives each 3 / 4 liter milk 20 cow gives each 1 / 4 liter milk this is split into 3 son per each 20 cows & 20 liter milk how ? 
Options: a ) 20 , b ) 10 , c ) 15 , d ) 16 , e ) 18
[A]:
a