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'.

Ex 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 21 seconds . the ratio of their speeds is ? 
Options: a ) 3 / 6 , b ) 3 / 2 , c ) 2 / 3 , d ) 3 / 5 , e ) 5 / 2

Ex Output:
c


Ex Input:
Problem: a can finish a piece of work in 12 days . b can do it in 20 days . they work together for 9 days and then a goes away . in how many days will b finish the work ? 
Options: a ) 6 days , b ) 4 days , c ) 5 days , d ) 3 days , e ) 7 days

Ex Output:
c


Ex Input:
Problem: a contractor undertakes to do a job within 100 days and hires 10 people to do it . after 20 days , he realizes that one fourth of the work is done so he fires 2 people . in how many more days q will the work get over ? 
Options: a ) q = 60 , b ) q = 70 , c ) q = 75 , d ) 80 , e ) 100

Ex Output:

c