Pipe P and Q can fill an empty tank individually in 9 hours and 12 hour respectively. If these are opened alternately every hour, starting with P, the pipe that fills the tank finally and the total time taken are given by

A

P fills and it takes $$10\frac{1}{4}$$

B

Q fills and it takes $$10\frac{1}{3}$$

C

P fills and it takes $$10\frac{1}{3}$$

D

Q fills and it takes $$10\frac{1}{4}$$