Explanation: The modulation index (m) for a Frequency Modulation (FM) signal is a fundamental parameter that describes the ratio of the maximum carrier frequency deviation to the maximum modulating frequency. It's calculated using the formula: m = $\Delta$f / fm Where: * $\Delta$f (delta f) is the maximum carrier frequency deviation (6 kHz in this case). * fm is the maximum modulating frequency (2 kHz in this case). Plugging in the given values: m = 6 kHz / 2 kHz = 3 Therefore, the modulation index is 3. Options B and C are incorrect because they represent the deviation and modulating frequency values themselves, not their ratio. Option D is incorrect as it would imply the deviation is equal to the modulating frequency, which is not the case here.