Explanation: Inductance (L) is a measure of a coil's ability to store energy in a magnetic field and oppose changes in current. The strength of the magnetic field produced by a coil is directly proportional to the number of turns (N). Furthermore, the induced voltage, and thus the inductance, is related to how effectively this magnetic field "links" with all the turns of the coil. Since the magnetic flux produced is proportional to N, and this flux links with N turns, the total magnetic flux linkages are proportional to N * N, or N squared (N²). Therefore, the inductance varies approximately as the square of the number of turns. Options B, C, and D are incorrect because the physical relationship between the coil's geometry and its magnetic properties dictates a square, not square root, dependency on the number of turns.