Explanation: A harmonic is an integer multiple of a fundamental frequency. The second harmonic is precisely twice the fundamental frequency. To find the second harmonic of 380 kHz, you simply multiply the fundamental frequency by two: 380 kHz * 2 = 760 kHz This is a core concept in radio theory, as electronic circuits, particularly amplifiers and transmitters, naturally generate harmonics in addition to the desired fundamental frequency. While the fundamental is the intended operating frequency, harmonics can be significant and must be considered for efficient operation and to prevent interference. Option A (1520 kHz) would be the fourth harmonic. Option C (190 kHz) is half of the fundamental frequency, often referred to as the second subharmonic, not a harmonic. Option D (2) is a numerical value, not a frequency.