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: tom drives from town q to town b , driving at a constant speed of 60 miles per hour . from town b tom immediately continues to town c . the distance between q and b is twice the distance between b and c . if the average speed of the whole journey was 36 mph , then what is tom ' s speed driving from b to c in miles per hour ? 
Options: a ) 12 , b ) 20 , c ) 24 , d ) 30 , e ) 36
Example Output: b

Example Input: Problem: a and b runs around a circular track . a beats b by one round or 10 minutes . in this race , they had completed 4 rounds . if the race was only of one round , find the a ' s time over the course : 
Options: ['a ) 8.5 min', 'b ) 7.5 min', 'c ) 1.5 min', 'd ) 9.5 min', 'e ) 4.5 min']
Example Output: b

Example Input: Problem: working alone at its constant rate , machine a produces x boxes in 5 minutes and working alone at its constant rate , machine b produces 2 x boxes in 10 minutes . how many minutes does it take machines a and b , working simultaneously at their respective constant rates , to produce 3 x boxes ? 
Options: a ) 3 minutes , b ) 7.5 minutes , c ) 5 minutes , d ) 6 minutes , e ) 12 minutes
Example Output:
b