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 cistern 8 m long and 6 m wide contains water up to a breadth of 1 m 85 cm . find the total area of the wet surface .
Options: a ) 102 m sqaure , b ) 100 m sqaure , c ) 152 m sqaure , d ) 164 m sqaure , e ) none of these
Example Output: b

Example Input: Problem: a train running at the speed of 120 km / hr crosses a pole in 18 seconds . what is the length of the train ?
Options: a ) 560 , b ) 570 , c ) 580 , d ) 590 , e ) 600
Example Output: e

Example Input: Problem: a and b together can do a piece of work in 6 days and a alone can do it in 12 days . in how many days can b alone can do it ?
Options: a ) 11 days , b ) 15 days , c ) 12 days , d ) 21 days , e ) 22 days
Example Output:
c