The Earth’s axis of rotation (polar axis) is always inclined at an angle of

The correct answer is D (23.5°). The Earth's polar axis is tilted about 23.5° (23°26' today, about 23.44°) from the perpendicular to the orbital plane, the ecliptic. This tilt, called obliquity, is the reason we have seasons. The option wording is loose: the angle is measured from the normal to the ecliptic, so the axis makes about 66.5° with the plane itself.

• A (23.0°) is a rounded-down figure, not the accepted value.
• B (23.1°) is too low for the standard value used in textbooks and exams.
• C (24.5°) is the upper extreme of the obliquity cycle, not the typical value. Obliquity oscillates between about 22.1° and 24.5° over roughly 41,000 years, which is one of the Milankovitch cycles.

Core concept: axial tilt and seasons, with the Sun's overhead position shifting between the Tropics of Cancer and Capricorn. Mains angle: links to climate change, Milankovitch cycles and why higher latitudes show sharper seasonal contrast.

Trap: Candidates pick 24.5° because it sounds more precise, or they mix up the ecliptic and equator as reference planes. Remember 23.5° as the standard value.