A 020-Km Wide River Has a Uniform Flow Speed of 4

Multiple Choice

A 0.20-km wide river has a uniform flow speed of 4.0 m/s toward the east.It takes 20 s for a boat to cross the river to a point directly north of its departure point on the south bank.In what direction must the boat be pointed in order to accomplish this?

A) 23 $\degree$ west of north
B) 20 $\degree$ west of north
C) 24 $\degree$ west of north
D) 22 $\degree$ west of north
E) 17 $\degree$ west of north