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'.

Example Input: Problem: a 600 meter long train crosses a signal post in 15 seconds . how long will it take to cross a 3 kilometer long bridge , at the same speed ? 
Options: a ) 4 min , b ) 2 min , c ) 8 min , d ) 9 min , e ) 1.5 min
Example Output: e

Example Input: Problem: a train running at the speed of 54 km / hr crosses a pole in 7 seconds . find the length of the train . 
Options: a ) 150 meter , b ) 105 meter , c ) 140 meter , d ) 135 meter , e ) none of these
Example Output: b

Example Input: Problem: a train 360 m long is running at a speed of 45 km / hr . in what time will it pass a bridge 340 m long ? 
Options: a ) 56 sec , b ) 42 sec , c ) 45 sec , d ) 48 sec , e ) 50 sec
Example Output:
a