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: ajay can ride 50 km in 1 hour . in how many hours he can ride 1250 km ? 
Options: a ) 10 hrs , b ) 15 hrs , c ) 20 hrs , d ) 25 hrs , e ) 18 hrs
Example Output: d

Example Input: Problem: how many paying stones , each measuring 2 m * 2 m are required to pave a rectangular court yard 30 m long and 18 m board ? 
Options: a ) 99 , b ) 18 , c ) 135 , d ) 17 , e ) 12
Example Output: c

Example Input: Problem: machine t takes 2 more hours than machine b to make 20 widgets . if working together , the machines can make 25 widgets in 3 hours , how long will it take machine t to make 40 widgets ? 
Options: a ) 5 , b ) 6 , c ) 8 , d ) 10 , e ) 12
Example Output:
e