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: a tree is 12 m tall and casts an an 8 m long shadow . at the same time , a flag pole caste a 100 m long shadow . how long is the flag pole ? 
Options: a ) 150 m , b ) 200 m , c ) 125 m , d ) 115 m , e ) none
Example Output: a

Example Input: Problem: a train is 300 meter long is running at a speed of 35 km / hour . in what time will it pass a bridge of 115 meter length ? 
Options: a ) 29 , b ) 23 , c ) 47.119 , d ) 44.586 , e ) 42.686
Example Output: e

Example Input: Problem: walking with 4 / 5 of my usual speed , i arrive at the bus stop 6 minutes later than normal . how many minutes does it take to walk to the bus stop at my usual speed ? 
Options: a ) 20 min , b ) 22 min , c ) 15 min , d ) 18 min , e ) 24 min
Example Output:
e