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 50 m long takes 6 sec to cross a man walking at 5 kmph in a direction opposite to that of the train . find the speed of the train ?
Options: a ) 15 kmph , b ) 25 kmph , c ) 35 kmph , d ) 45 kmph , e ) 55 kmph
Example Output: b

Example Input: Problem: a garrison of 1850 men has provisions for 28 days . at the end of 12 days , a reinforcement arrives , and it is now found that the provisions will last only for 10 days more . what is the reinforcement ?
Options: a ) 1850 , b ) 2960 , c ) 3000 , d ) 1110 , e ) 1712
Example Output: d

Example Input: Problem: due to construction , the speed limit along an 10 - mile section of highway is reduced from 55 miles per hour to 15 miles per hour . approximately how many minutes more will it take to travel along this section of highway at the new speed limit than it would have taken at the old speed limit ?
Options: a ) a ) 6.24 , b ) b ) 8 , c ) c ) 29.1 , d ) d ) 15 , e ) e ) 24
Example Output:
c