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 Input:
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 .

Ex Output:
a


Ex Input:
Problem: find the least number which when divided by 18,32 , 48,52 leaves remainder 14,28 , 44,48 respectively . 
Options: a ) 2845 , b ) 3250 , c ) 3740 , d ) 4150 , e ) 5140

Ex Output:
c


Ex Input:
Problem: at the end of the day , february 14 th , a florist had 150 roses left in his shop , all of which were red , white or pink in color and either long or short - stemmed . a third of the roses were short - stemmed , 20 of which were white and 15 of which were pink . the percentage of pink roses that were short - stemmed equaled the percentage of red roses that were short - stemmed . if none of the long - stemmed roses were white , what percentage of the long - stemmed roses were red ? 
Options: a ) 50 % , b ) 25 % , c ) 250 % , d ) 75 % , e ) 80 %

Ex Output:

a