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 and b together can do a piece of work in 10 days . b alone can finish it in 20 days . in how many days can a alone finish the work ? 
Options: a ) 20 , b ) 10 , c ) 15 , d ) 5 , e ) 7
Example Output: a

Example Input: Problem: in a garden , there are 10 rows and 12 columns of mango trees . the distance between the two trees is 2 metres and a distance of one metre is left from all sides of the boundary of the garden . the length of the garden is ? 
Options: a ) 12 , b ) 27 , c ) 24 , d ) 29 , e ) 11
Example Output: c

Example Input: Problem: a factory produces 6500 toys per week . if the workers at this factory work 5 days a week and if these workers make the same number of toys everyday , how many toys are produced each day ? 
Options: a ) 1375 toys , b ) 2375 toys , c ) 1300 toys , d ) 1375 toys , e ) 2375 toys
Example Output:
c