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'.

Input: Consider Input: Problem: if a : b = 2 : 3 , b : c = 4 : 5 and c : d = 5 : 9 then a : d is equal to : 
Options: a ) 11 : 17 , b ) 8 : 27 , c ) 5 : 9 , d ) 2 : 9 , e ) none

Output: b


Input: Consider Input: Problem: in a competitive examination in a state a , 10 % candidates got selected from the total appeared candidates . state b had an equal number of candidates appeared and 12 % candidates got selected with 100 more candidates got selected than a . what was the number of candidates appeared from each state ? 
Options: a ) 4000 , b ) 5000 , c ) 5500 , d ) 6500 , e ) 4200

Output: b


Input: Consider Input: Problem: in a river flowing at 2 km / hr , a boat travels 48 km upstream and then returns downstream to the starting point . if its speed in still water be 6 km / hr , find the total journey time . 
Options: a ) 10 hours , b ) 12 hours , c ) 14 hours , d ) 18 hours , e ) none of these


Output: d