In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Input: Consider Input: Problem: three pipes of same capacity can fill a tank in 8 hours . if there are only two pipes of same capacity , the tank can be filled in . 
Options: a ) 11 hours , b ) 12 hours , c ) 15 hours , d ) 16 hours , e ) 17 hours

Output: b


Input: Consider Input: Problem: how long does a train 165 meters long running at the rate of 54 kmph take to cross a bridge 660 meters in length ? 
Options: a ) 55 sec , b ) 40 sec , c ) 45 sec , d ) 30 sec , e ) 35 sec

Output: a


Input: Consider Input: Problem: two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 25 seconds . the ratio of their speeds is ? 
Options: a ) 3 / 1 , b ) 4 / 1 , c ) 3 / 3 , d ) 3 / 5 , e ) 5 / 2


Output: b