Explanation: Frequency counters derive their accuracy from their internal time base oscillator. A time base accuracy of +/- 10 ppm (parts per million) means that for every million units of the measured frequency, there could be an error of 10 units. To calculate the maximum possible difference, multiply the measured frequency by the ppm error expressed as a fraction: Error = Measured Frequency × (ppm / 1,000,000) Error = 156,520,000 Hz × (10 / 1,000,000) Error = 156,520,000 Hz × 0.000010 Error = 1565.20 Hz Therefore, the actual transmitter frequency could differ from the reading by as much as 1565.20 Hz in either direction. This makes option B the correct answer. Options A, C, and D represent incorrect calculations or orders of magnitude.