How can the magnetic field around a magnet be mapped using a compass?

How can the magnetic field around a magnet be mapped using a compass?

• A. Move a compass around the magnet and plot the direction of the needle; the plotted lines show the field.
• B. Use a voltmeter to measure field strength.
• C. Submerge in water and observe.
• D. Use a ruler to measure length of field lines.

Answer: (A)