Definition: 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'.
Input: Problem: a and b can do a piece of work in 2 days , b and c in 3 days , c and a in 4 days . how long will c take to do it ? 
Options: a ) 14 days , b ) 20 days , c ) 22 days , d ) 24 days , e ) 26 days
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
d