Explanation: Frequency counter accuracy, often expressed in parts per million (ppm), indicates the maximum potential deviation of the measured frequency from the actual frequency. A time base accuracy of ± 1.0 ppm means the error is 1.0 part per million of the displayed frequency. To calculate the maximum possible difference, multiply the displayed frequency by the ppm value and then divide by 1,000,000: Deviation = Displayed Frequency × (ppm / 1,000,000) Deviation = 462,100,000 Hz × (1.0 / 1,000,000) Deviation = 462,100,000 Hz / 1,000,000 Deviation = 462.1 Hz This means the actual frequency could be 462.1 Hz higher or lower than the 462,100,000 Hz reading. A) 46.21 MHz is a restatement of the frequency, not the error. B) 10 Hz is far too small for this frequency range. C) 1.0 MHz is a vastly excessive error, representing thousands of ppm.