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'.

Example Input: Problem: a mixture contains alcohol and water in the ratio 4 : 3 . if 8 litres of water is added to the mixture , the ratio becomes 4 : 5 . find the quantity of alcohol in the given mixture 
Options: a ) 15 litres , b ) 10 litres , c ) 30 litres , d ) 22 litres , e ) 16 litres
Example Output: e

Example Input: Problem: a confectioner decides to sell all of his pastry due to the coming holiday . his pastry goods are equally divided among a group of 28 regular customers . if only 49 customers come to the bakery , each one will receive 6 less pastry goods . how much pastry does the confectioner needs to sell ? 
Options: a ) 392 , b ) 412 . , c ) 432 . , d ) 502 , e ) 522
Example Output: a

Example Input: Problem: the largest 4 digit number exactly divisible by 90 is ? 
Options: a ) 9935 , b ) 9939 , c ) 9944 , d ) 9954 , e ) 9990
Example Output:
e