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 and b can do a piece of work in 8 days . with the help of c they finish the work in 4 days . c alone can do that piece of work in ? 
Options: a ) 40 days , b ) 20 days , c ) 8 days , d ) 60 days , e ) 40 days

Output: c


Input: Consider Input: Problem: a train of length 250 m runs at a speed of 70 km / hr . what will be the time taken to cross any stationary object standing at the railway station ? 
Options: a ) 20 sec , b ) 17.23 sec , c ) 12.86 sec , d ) 9.5 sec , e ) 8.5 sec

Output: c


Input: Consider Input: Problem: what is the radius of a circle that has a circumference of 3.14 meters ? 
Options: ['a ) 2.5', 'b ) 2', 'c ) 1.5', 'd ) 1', 'e ) 0.5']


Output: e