[单选题]
A boat can travel 4.0 m/s in still water. With whatj-gx,5zd psf; .wr.u o spee8 d, ymo(bhot9c:0 zpt/nk v(rd, relative to the shore, d b,(yo/( 0 dtmp:rc8ton9hkvz oes it move in a river that is flowing at 1.0 m/s if the boat is heading straight across the river?