How is true bearing related to magnetic bearing?

True bearing and magnetic bearing are fundamentally different due to the Earth's magnetic field's characteristics and how they interact with the geographic coordinate system. True bearing refers to the angle measured in degrees in relation to true north, which is the direction towards the North Pole. On the other hand, magnetic bearing is measured in relation to magnetic north, which can shift due to changes in the Earth's magnetic field and local geological conditions.

To convert magnetic bearing to true bearing, one must consider the magnetic declination, which is the angle difference between true north and magnetic north at a specific location. This means a conversion based on declination is necessary to obtain true bearing from magnetic bearing.

This understanding clarifies why the choice relating to conversion based on declination is the correct answer. The other choices do not accurately represent the relationship between true bearing and magnetic bearing; for instance, some may imply incorrect assumptions about their measurements or adjustments without addressing the essential need to convert using declination.