Final answer:
A dipolar bar magnet has two poles, north and south, making the correct option number 3: two poles.
Step-by-step explanation:
A bar magnet is described as dipolar, indicating that it has two poles: a north pole and a south pole. Your question, "A bar magnet is dipolar. This means it has how many poles?", can be answered as option 3) which is two poles. It is an intrinsic property of a magnet to always have two opposite poles, whether it is a large bar magnet or a small piece of magnet. Cutting a bar magnet in half will not separate its north pole from its south pole; each new piece will again have a north and a south pole. In essence, magnetics are always dipoles which result in the magnetic dipole moment.