The correct answer is option A, Orbital plane.

Explanation:
The plane formed by the axis of the Earth and its orbit around the Sun is known as the orbital plane. This plane represents the path that the Earth follows as it revolves around the Sun.

Here is a detailed explanation of the concept:

1. Earth's Axis: The Earth rotates on an imaginary line called its axis. This axis is an imaginary vertical line that passes through the North and South Poles of the Earth. It remains tilted at an angle of approximately 23.5 degrees with respect to the plane of its orbit around the Sun.

2. Earth's Orbit: The Earth revolves around the Sun in an elliptical path known as its orbit. This orbit is the result of the gravitational attraction between the Earth and the Sun. It takes approximately 365.25 days for the Earth to complete one orbit around the Sun, resulting in the change of seasons.

3. Formation of the Orbital Plane: The plane formed by the axis of the Earth and its orbit around the Sun is known as the orbital plane. It is an imaginary flat surface that represents the average position of the Earth's orbit in space. The orbital plane is inclined at an angle of approximately 23.5 degrees to the plane of the Earth's equator.

4. Significance of the Orbital Plane: The orbital plane is significant because it determines the position of the Sun in the sky as seen from different locations on Earth. It also affects the distribution of sunlight on Earth's surface, causing variations in seasons.

In conclusion, the plane formed by the axis of the Earth and its orbit around the Sun is known as the orbital plane. It represents the path that the Earth follows as it revolves around the Sun and is inclined at an angle of approximately 23.5 degrees to the plane of the Earth's equator.