Subject: mathqa
Question: a and b can finish a work together in 12 days , and b and c together in 16 days . if a alone works for 5 days and then b alone continues for 7 days , then remaining work is done by c in 13 days . in how many days can c alone finish the complete work ?
Option: 
A: 22 days
B: 24 days
C: 25 days
D: 21 days
Answer: B