P can do a piece of work in 200 days. Q and R can do the same work in 100 days. P, Q and R started the work together and they worked together for 40 days and then Q left the work and P and R together finished the remaining work in 40 days. Find the number of days in which Q alone can do the total work.

A

160 days

B

210 days

C

180 days

D

200 days