Which statement is true regarding magnetic variation?

Magnetic variation, also known as magnetic declination, is the angle that exists between true north, which is based on the fixed geographic North Pole, and magnetic north, which is determined by the Earth's magnetic field. This angle is not constant and varies depending on geographical location.

Understanding this concept is essential for navigation, as pilots must recognize that the compass indicates magnetic north and not true north, requiring adjustments in their navigation calculations to ensure accuracy. In most cases, magnetic variation will change over time and can differ from one location to another, making accurate navigation critically dependent on knowing the specific magnetic variation for the area being flown.

The other statements either misrepresent the nature of magnetic variation or suggest that it does not change with geographical differences or over time, which is not the case.