Answer : 4. "Oblate Sphere "
Explanation :

The Earth is not a perfect sphere but is slightly flattened at the poles and bulging at the equator due to its rotation. This shape is often referred to as an oblate spheroid, meaning it is mostly spherical but slightly flattened at the poles and slightly bulging at the equator. The flattening is a result of the Earth's rotation, which causes it to be slightly compressed along its axis.