John walks to school in the morning and then walks home for lunch. the school is 1000 meters directly north of his house. after lunch, he goes back to the school and then to the field for track that is 30 meters north of the school. what is john's resultant displacement when he remains on the field to run track?
a. 30 meters north
b. 970 meters north
c. 1030 meters north
d. 3000 meters north

think its b, but i want a second opinion