X, Y are two points in a river. Points P and Q divide the straight line XY into three equal parts. The river flows along XY_andthe time taken by a boat to row from X to Q and from Y to Q are in the ratio 4 : 5. Theratio of the speed of the boat downstream to that of the river current is equal to:

A

3 : 10

B

10 : 3

C

3 : 4

D

4 : 3