Final answer:
The magnetic field produced by a bar magnet is similar to Earth's magnetic field, both having two poles, a north and south pole. However, Earth's magnetic field has three poles, unlike the bar magnet.
Step-by-step explanation:
The magnetic field produced by a bar magnet can be made visible using iron filings, which align to the magnetic field. The image shows the iron filings aligning with the magnetic field lines of the bar magnet. Earth's magnetic field is similar to that of a giant bar magnet, with two magnetic poles, a north pole, and a south pole, just like a bar magnet.
Therefore, the correct answer is option b: The bar magnet has two poles at W and Y, but the magnetic field produced by Earth has three poles and looks different from the bar magnet.