A Swimmer Heading Directly Across a River 200 M Wide

A swimmer heading directly across a river 200 m wide reaches the opposite bank in 6 min 40 s. She is swept downstream 300 m. How fast can she swim in still water?

A) 1.83 m/s
B) 1.42 m/s
C) 0.50 m/s
D) 1.24 m/s
E) 0.25 m/s