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: a river boat leaves silver town and travels upstream to gold town at an average speed of 6 kilometers per hour . it returns by the same route at an average speed of 5 kilometers per hour . what is the average speed for the round - trip in kilometers per hour ?
Options: a ) 5.5 , b ) 7.1 , c ) 7.2 , d ) 7.0 , e ) 8.0

Ex Output:
a

Ex Input:
Problem: calculate how many days it will take for 5 boys to paint a 30 m long fence if 2 boys can paint a 20 m long fence in 3 days ,
Options: a ) 6.80 days , b ) 4.80 days , c ) 3.80 days , d ) 2 days , e ) 1.80 days

Ex Output:
e

Ex Input:
Problem: a 1200 m long train crosses a tree in 120 sec , how much time will i take to pass a platform 1100 m long ?
Options: a ) 200 sec , b ) 230 sec , c ) 167 sec , d ) 197 sec , e ) 179 sec

Ex Output:
b