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: how long does a train 110 m long running at the speed of 72 km / hr takes to cross a bridge 112 m length ?
Options: a ) 82.1 sec , b ) 12.1 sec , c ) 16.1 sec , d ) 11.1 sec , e ) 12.15 sec
Example Output: d

Example Input: Problem: a horse chases a pony 8 hours after the pony runs . horse takes 12 hours to reach the pony . if the average speed of the horse is 320 kmph , what s the average speed of the pony ?
Options: a ) 182 kmph , b ) 192 kmph , c ) 193 kmph , d ) 196 kmph , e ) 190 kmph
Example Output: b

Example Input: Problem: x is able to do a piece of work in 14 days and y can do the same work in 20 days . if they can work together for 5 days , what is the fraction of work completed ?
Options: a ) 15 / 28 , b ) 17 / 28 , c ) 13 / 28 , d ) 19 / 28 , e ) 11 / 28
Example Output:
b