Question 672Navigation General

The correct answer is A) the magnetic poles. The points on the earth's surface where the magnetic dip is 90° are the magnetic poles, where the earth's magnetic field lines are perpendicular to the surface. At the magnetic poles, the magnetic field lines are vertical, resulting in a magnetic dip of 90°. The other answer choices are incorrect: B) isoclinal lines connect points with the same magnetic dip, not necessarily 90°; C) isopors are lines connecting points with the same rate of change in magnetic declination, not dip; and D) the magnetic equator is where the magnetic dip is 0°, not 90°.