A Boat Crosses a River Which Is Flowing at 6

Multiple Choice

A boat crosses a river which is flowing at 6.0 m/s.The boat travels directly across the river from A to B and the speed of the boat relative to the river is 10.0 m/s.While it is crossing the river,what is the speed of the boat relative to the shore (point a)

A) 4.0 m/s
B) 12.4 m/s
C) 11.7 m/s
D) 16.0 m/s
E) 8.0 m/s