Correct Answer : Correcting resonance to a desired frequency
Explanation : When a vertical antenna is made less than one-quarter wavelength, the practical effect is a decreased inductance. The antenna no longer resonates at the desired operating frequency, but at a higher frequency. To compensate for this, a series inductor, called a loading coil, is connected in series with the antenna coil. The loading coil brings the antenna back into resonance at the desired frequency.