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 train 284 m in length crosses a telegraph post in 18 seconds . the speed of the train is ? 
Options: a ) 77 kmph , b ) 55 kmph , c ) 57 kmph , d ) 58 kmph , e ) 76 kmph
Example Output: c

Example Input: Problem: if teena is driving at 55 miles per hour and is currently 7.5 miles behind loe , who is driving at 40 miles per hour in the same direction then in how many minutes will teena be 15 miles ahead of loe ? 
Options: a ) 15 , b ) 60 , c ) 75 , d ) 90 , e ) 105
Example Output: d

Example Input: Problem: a man , a woman and a boy can together complete a piece of work in 3 days . if a man alone can do it in 6 days and a boy alone in 18 days , how long will a woman take to complete the work ? 
Options: a ) 9 days , b ) 21 days , c ) 24 days , d ) 27 days , e ) 28 days
Example Output:
a