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: if a train , travelling at a speed of 180 kmph , crosses a pole in 5 sec , then the length of train is ? 
Options: a ) 250 m , b ) 112 m , c ) 117 m , d ) 125 m , e ) 123 m

Output: a


Input: Consider 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

Output: a


Input: Consider Input: Problem: if the population of a certain country increases at the rate of 1 person every 60 seconds , by how many persons does the population increase in 2 hours ? 
Options: a ) 120 , b ) 80 , c ) 100 , d ) 150 , e ) 140


Output: a