Just like other magnets, the Earth has A. two positively charged magnetic poles. B. only one magnetic pole. C. two negatively charged magnetic poles. D. two opposite magnetic poles.

The correct answer is D. two opposite magnetic poles.

From the outside, the magnets behave as if they had a north magnetic monopole inside the ''N'' (North) end and a south magnetic monopole inside the ''S'' (South) end. So practically, they act as magnetic dipoles, or with other words, on one side there is positive charge up, while on the other side there is negative charge up.