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: an seller earns an income of re 1 on the first day of his business . on every subsequent day , he earns an income which is just thrice of that made on the previous day . on the 20 th day of business , he earns an income of : 
Options: a ) 29 , b ) 57 , c ) 35 , d ) 20 , e ) 30
Example Output: b

Example Input: Problem: the radius of a wheel is 22.6 cm . what is the distance covered by the wheel in making 750 resolutions ? 
Options: a ) 754 m , b ) 704 m , c ) 1055.04 m , d ) 1058.04 m , e ) 204 m
Example Output: c

Example Input: Problem: a car covers a distance of 642 km in 6 ½ hours . find its speed ? 
Options: a ) 104 kmph , b ) 176 kmph , c ) 298 kmph , d ) 186 kmph , e ) 107 kmph
Example Output:
e