Explanation:

- Option 1: A circle

- This is not accurate for the Earth. A circle is two-dimensional, while the Earth is three-dimensional.

- Option 2: A sphere

- This is a close description, but the Earth is not a perfect sphere. It is slightly flattened at the poles.

- Option 3: A geoid

- This is the most scientifically accurate. "Geoid" means the shape that the Earth's surface would take under only gravity and rotation, slightly irregular.

- Option 4: An oblate sphere

- This means a sphere flattened at the poles and bulging at the equator. This is a very accurate everyday description of the Earth, though "oblate spheroid" is the precise term.