If you have ever used a compass, you know that it can be used to navigate. it does this with a needle that always points north, so you know which direction you are heading. why does a compass needle point north?

a)due to the direction of the earth's orbit.
b)due to the influence of the earth's rotation.
c)due to the influence of the earth's magnetic field.
d)due to the influence of the earth's electric field.