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: the distance between west - town to east - town is 20 kilometers . two birds start flying simultaneously towards one another , the first leaving from west - town at a speed of 4 kilometers per minute and the second bird , leaving from east - town , at a speed of 1 kilometers per minute . what will be the distance , in kilometers , between the meeting point and west - town ? 
Options: a ) 3 . , b ) 7 . , c ) 10 . , d ) 16 . , e ) 15 .
Example Output: d

Example Input: Problem: a 180 meter long train crosses a man standing on the platform in 9 sec . what is the speed of the train ? 
Options: a ) 72 , b ) 108 , c ) 1266 , d ) 188 , e ) 211
Example Output: a

Example Input: Problem: car x began traveling at an average speed of 35 miles per hour . after 36 minutes , car y began traveling at an average speed of 38 miles per hour . when both cars had traveled the same distance , both cars stopped . how many miles did car x travel from the time car y began traveling until both cars stopped ? 
Options: a ) 105 , b ) 140 , c ) 175 , d ) 210 , e ) 245
Example Output:
e