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 train 300 m long takes 9 sec to cross a man walking at 3 kmph in a direction opposite to that of the train . find the speed of the train ? 
Options: a ) 100 kmph , b ) 90 kmph , c ) 120 kmph , d ) 117 kmph , e ) 125 kmph
Example Output: d

Example Input: Problem: a factory produces 4560 toys per week . if the workers at this factory work 4 days a week and if these workers make the same number of toys everyday , how many toys are produced each day ? 
Options: a ) 1140 toys , b ) 2375 toys , c ) 3375 toys , d ) 4375 toys , e ) 5375 toys
Example Output: a

Example Input: Problem: a woman swims downstream 45 km and upstream 15 km taking 3 hours each time , what is the speed of the woman in still water ? 
Options: a ) 10 , b ) 12 , c ) 14 , d ) 16 , e ) 18
Example Output:
a