A student marks his starting point on a grassy field. He then makes three moves: 20 m east, 70 m north, and 80 m west. Where is his final position relative to his starting point?
60 m east and 70 m south
60 m west and 70 m north
60 m east and 70 m north
70 m west and 60 m north
70 m east and 60 m south