Becca paddles a boat from the south bank of a stream to the north bank. she paddles at a rate of 8 mph. the stream is flowing west at a rate of 6 mph. which of the following diagrams best illustrates the actual path of the boat?

The first one is correct.  It shows her paddling at 8mph north and the water moving 6mph west.  Importantly it also has the vectors added correctly.  You draw all the vectors head to tail then the resultant vector is drawn from the base of the first one to the head of the last one with the arrow pointing in that direction.