It says that's 4 units distant from the another vertex. So, if a square is formed by 4 equal sides and 4 right angles, then you just have to add 4 units on x or y.
-> (2, 1) -> + 4 units on X -> = (6, 1) or -> (2, 1) -> +4 units on Y -> = (2, 5)
(2, 5) isn't an answer so the unique possible answer is (6, 1)
as the point (8,0) lies on the x-axis (east) and the bearings are defined with respect to south or north according to the rotation as well. so here the angle is 90 and the directions are N90E or S90W
