Explanation: The accuracy of a frequency counter's time base determines the potential error in its reading. A time base accuracy of ± 0.1 ppm (parts per million) means the frequency reading could be off by 0.1 parts per million of the measured frequency. To calculate the maximum possible difference, multiply the transmit frequency by the accuracy: 462,100,000 Hz * (0.1 / 1,000,000) = 462,100,000 Hz * 0.0000001 = 46.21 Hz. Therefore, the actual transmit frequency could differ from the counter's reading by as much as 46.21 Hz in either direction (above or below the reading). This is a critical concept in maintaining spectral purity and operating within allocated frequency bands. Options B and D are incorrect as 0.1 MHz (100,000 Hz) and 0.2 MHz (200,000 Hz) are significantly larger deviations than calculated. Option C, 462.1 Hz, would represent a 1 ppm error, not 0.1 ppm.