Explanation: The deviation ratio for an FM signal is a key parameter that describes the relationship between its maximum frequency swing and the highest modulating frequency. It is calculated by dividing the maximum frequency deviation (or peak frequency swing) by the highest modulating frequency. Using the provided values: Maximum frequency swing ($\Delta$f) = 7.5 kHz Maximum modulation rate (f$_{m(max)}$) = 3.5 kHz Deviation Ratio = $\Delta$f / f$_{m(max)}$ Deviation Ratio = 7.5 kHz / 3.5 kHz = 2.1428... Rounding to two decimal places, the deviation ratio is 2.14. Option A is correct. Option B results from incorrect decimal placement. Option C results from inverting the ratio (3.5/7.5). Option D is incorrect by a large magnitude.