Two bar magnets are labeled a and b. the ends of each magnet are numbered 1 or 2, but the poles are not labeled. when a1 is brought near b1, the bars repel. which conclusion is best supported by the data?

a. a1 is the north pole of a magnet, and b1 is the south pole of a magnet.
b. a1 is the north pole of a magnet, and b1 is the north pole of a magnet.
c. a1 and b1 are opposite poles, but there is not enough information to tell which ones.
d. a1 and b1 are like poles, but there is not enough information to tell whether they are north poles or south poles.