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'.

Example Input: Problem: if the product of two numbers is 45276 and their h . c . f . is 22 , find their l . c . m . 
Options: a ) 2574 , b ) 2500 , c ) 2100 , d ) 2058 , e ) none of these
Example Output: d

Example Input: Problem: a man sitting in a train which is travelling at 64 kmph observes that a goods train travelling in a opposite direction , takes 18 seconds to pass him . if the goods train is 420 m long , find its speed . 
Options: a ) 32 , b ) 15 , c ) 18 , d ) 20 , e ) 25
Example Output: d

Example Input: Problem: how many seconds will a 600 meter long train take to cross a man walking with a speed of 3 km / hr in the direction of the moving train if the speed of the train is 63 km / hr ? 
Options: a ) 700 , b ) 288 , c ) 500 , d ) 277 , e ) 121
Example Output:
a