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: two trains of equal lengths take 10 sec and 15 sec respectively to cross a telegraph post . if the length of each train be 200 m , in what time will they cross other travelling in opposite direction ? 
Options: a ) 17 sec , b ) 12 sec , c ) 16 sec , d ) 15 sec , e ) 20 sec
Example Output: e

Example Input: Problem: a train , 800 meter long is running with a speed of 78 km / hr . it crosses a tunnel in 1 minute . what is the length of the tunnel ? 
Options: a ) 650 meter , b ) 555 meter , c ) 500 meter , d ) 458 meter , e ) none of these
Example Output: c

Example Input: Problem: a cistern 6 m long and 4 m wide contains water up to a breadth of 1 m 25 cm . find the total area of the wet surface . 
Options: a ) 66 m square , b ) 49 m square , c ) 77 m square , d ) 44 m square , e ) 33 m square
Example Output:
b