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: a can do a piece of work 60 days . b can do work in 20 days . in how many days they will complete the work together ? 
Options: a ) 12 days , b ) 16 days , c ) 15 days , d ) 17 days , e ) 18 days

Output: c


Input: Consider Input: Problem: two trains are moving in opposite directions with speed of 90 km / hr and 90 km / hr respectively . their lengths are 1.10 km and 0.9 km respectively . the slower train cross the faster train in - - - seconds 
Options: a ) 56 , b ) 40 , c ) 47 , d ) 26 , e ) 25

Output: b


Input: Consider Input: Problem: a is twice as good a workman as b and they took 8 days together to do the work b alone can do it in . 
Options: a ) 24 days , b ) 12 days , c ) 29 days , d ) 25 days , e ) 27 days


Output: a