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 jeep takes 3 hours to cover a distance of 440 km . how much should the speed in kmph be maintained to cover the same direction in 1 / 2 th of the previous time ?
Options: a ) 48 kmph , b ) 252 kmph , c ) 293 kmph , d ) 263 kmph , e ) 265 kmph
Example Output: c

Example Input: Problem: if 8 men or 12 women can do a piece of work in 20 days , in how many days can the same work be done by 6 men and 11 women ?
Options: a ) 10 days , b ) 11 days , c ) 12 days , d ) 15 days , e ) 17 days
Example Output: c

Example Input: Problem: machine a can process 6000 envelopes in 3 hours . machines b and c working together but independently can process the same number of envelopes in 2.5 hours . if machines a and c working together but independently process 3000 envelopes in 1 hour , then how many hours would it take machine b to process 7000 envelopes .
Options: a ) 2 , b ) 3 , c ) 4 , d ) 5 , e ) 60 / 7
Example Output:
d