A disoriented physics professor drives 3.25 km due north, then 4.75 km west, and then 1.50 km due south. Find the magnitude and direction of the resultant.
A. Magnitude: 5.75 km; Direction: West
B. Magnitude: 3.25 km; Direction: North
C. Magnitude: 4.75 km; Direction: East
D. Magnitude: 6.25 km; Direction: South