P can do a piece of work in 30 days and Q can do the same work in 40 days. They worked together for 5 days and then Q left. How much time (in days and hours) will P, working alone, take to complete the remaining work?

A

21 days 6 hours

B

21 days 18 bours

C

21 days 12 bours

D

20 days 6 hours