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 bicycle wheel has a diameter of 0.51 m . how many complete revolutions does it make in 1 km ? 
Options: a ) 246 , b ) 448 , c ) 1408 , d ) 710 , e ) 624
Example Output: e

Example Input: Problem: an engineer undertakes a project to build a road 10 km long in 150 days and employs 30 men for the purpose . after 50 days , he finds only 2 km of the road has been completed . find the ( approximate ) number of extra men he must employ to finish the work in time . 
Options: a ) 22 , b ) 30 , c ) 15 , d ) 18 , e ) 20
Example Output: b

Example Input: Problem: if 4 men working 10 hours a day earn rs . 1600 per week , then 9 men working 6 hours a day will earn how much per week ? 
Options: a ) rs 840 , b ) rs 1320 , c ) rs 1620 , d ) rs 2160 , e ) none of these
Example Output:
d