P, Q and R can complete a work alone in 12, 15 and 20 days respectively. They started the work together. P left the work 8 days before the work was completed and Q left the work 5 days after P had left. R completed the remaining work alone. How many days will be required to complete the whole work?

A

32/3 days

B

10 days

C

28/3 days

D

25/3 days