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 man is standing on a railway bridge which is 180 m long . he finds that a train crosses the bridge in 20 seconds but himself in 8 seconds . find the length of the train and its speed 
Options: a ) 50 km , b ) 52 km , c ) 54 km , d ) 56 km , e ) 58 km

Output: c


Input: Consider Input: Problem: a can do a piece of work in 10 days . he works at it for 4 days and then b finishes it in 9 days . in how many days can a and b together finish the work ? 
Options: a ) 6 , b ) 7 , c ) 5 , d ) 4 , e ) 1

Output: a


Input: Consider Input: Problem: a train covers a distance of 100 km in 1 hour . if its speed is decreased by 10 km / hr , the time taken by the car to cover the same distance will be ? 
Options: a ) 1 hr , b ) 1 hr 6 min , c ) 50 min , d ) 1 hr 30 min , e ) 1 hr 45 min


Output: b