A Girl Wishes to Swim Across a River to a Point

Multiple Choice

A girl wishes to swim across a river to a point directly opposite as shown.She can swim at 2 m/s in still water and the river is flowing at 1 m/s.At what angle $\theta$ with respect to the line joining the starting and finishing points should she swim?

A) 30°
B) 45°
C) 60°
D) 63°
E) 90°