Explanation:

- Correct Answer: Option 3: Tilt of Earth

- The primary reason for the seasons is the tilt of Earth's axis in relation to its orbital plane around the Sun. This tilt (approximately 23.5 degrees) causes different parts of Earth to receive varying amounts of sunlight throughout the year.

- Option 1: Rotation

- Earth's rotation on its axis occurs roughly every 24 hours and results in day and night, not seasonal changes.

- Option 2: Revolution

- Earth's revolution around the Sun over the course of a year contributes to the seasonal cycle by changing Earth's position in its orbit, but it is the axial tilt that primarily causes the seasons.

- Option 4: Position of Earth

- While Earth's position in its elliptical orbit can slightly affect the intensity of seasons, it is the axial tilt that leads to the significant seasonal weather patterns due to varying sunlight distribution.