Concept:Angle of dip (or inclination) is the angle made by Earth's magnetic field with the horizontal. At magnetic poles, field is vertical, so dip is 90°.
Explanation:Earth acts like a giant bar magnet. Its magnetic field lines emerge from the south magnetic pole and enter the north magnetic pole.
At the magnetic equator, the field is horizontal, so dip angle is 0°. At the magnetic poles, the field lines are vertical (straight up or down), so the dip needle points straight down — making the dip angle 90°.
Hence, at Earth's magnetic north and south poles, the dip is 90°. The horizontal intensity there is zero, and a compass needle becomes useless.
Answer:The angle of dip at the magnetic pole of Earth is 90°. So the correct option is C. 90°.