What accounts for the difference between magnetic north and true north?

The correct answer is magnetic declination, which refers to the angle between magnetic north, the direction a compass points, and true north, the geographic North Pole. This angle is important to consider when using a compass for navigation and mapping since it translates to a difference in how direction is perceived by navigation tools versus the actual geographic layout of the earth.

Magnetic declination varies depending on your location on the earth’s surface and can change over time due to changes in the earth's magnetic field. When navigating or working with maps, an understanding of this difference is essential for accurate readings and positioning.

The other concepts listed, such as a north arrow, true bearings, and magnetic intervals, relate to navigation and mapping but do not directly define the difference between magnetic north and true north. A north arrow simply indicates direction on a map but doesn't account for declination. True bearings refer to the accurate direction of geographic features, while magnetic intervals are not typically used as a technical term in geographic context. These aspects are important in navigation, but they do not address the specific angular measurement that distinguishes magnetic north from true north.