P, Q and R, when working individually, can complete a job in, respectively, 36 days, 48 days and 144 days. P, Q and R start working together. P leaves the job 12 days before completion and Q leaves the job 8 days before completion. R works from the beginning till the end of the job. Determine the total number of days taken to complete the job.

A

24

B

27

C

30

D

25