The speed of sound in a gas depends on its temperature and molecular characteristics. The speed of sound (\(v_s\)) is calculated using the formula: \[ v_s = \sqrt{\frac{\gamma R T}{M}} \] In this equation, \(\gamma\) represents the adiabatic index, \(R\) is the universal gas constant, \(T\) denotes the temperature, and \(M\) signifies the molar mass. A monoatomic ideal gas has an average of 3 degrees of freedom (\(f = 3\)). A gas with 6 degrees of freedom behaves as a diatomic gas, with an adiabatic index of \(\gamma = 1.4\). The relationship between the root mean square (rms) speed (\(c\)) and the velocity of sound is: \[ v_s = \frac{c}{\sqrt{3}} \] Therefore, the correct answer is \(c/\sqrt{3}\).