Anna learned that every magnet has a north and a south end called poles. One day, while she is playing with magnets she notices that when she puts the north end of a magnet near the south end of another magnet, they pull together. What can Anna conclude from her observation?
A) Opposite poles of magnets repel.
B) Opposite poles of magnets attract.
C) The north pole picks up iron nails.
D) Only the north pole has an attractive force.