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: in a 200 meter race a beats b by 35 meters in 7 seconds . a ' s time over the cause is ? 
Options: a ) 47 sec , b ) 40 sec , c ) 45 sec , d ) 33 sec , e ) 35 sec
Example Output: d

Example Input: Problem: 9 spheres of the same size are made from melting a solid cylinder of 16 cm diameter and 12 cm height . what is the diameter of each sphere ? 
Options: ['a ) 4 cm', 'b ) 6 cm', 'c ) 8 cm', 'd ) 10 cm', 'e ) 12 cm']
Example Output: c

Example Input: Problem: a train is 360 meter long is running at a speed of 45 km / hour . in what time will it pass a bridge of 140 meter length . 
Options: a ) 20 seconds , b ) 27 seconds , c ) 30 seconds , d ) 40 seconds , e ) 50 seconds
Example Output:
d