For sound waves the Doppler formula the frequency shift differs slightly between the two situation (i) source at rest; observe moving (ii) source moving ; observing at rest . The exact Doppler formula for the case light waves in vacuum , are however strictly ideal for the two situation in case of light travelling in a medium ?

Question

$\begin{array}{1 1} \text{Sound waves need a medium for propagation} \\ \text{Doppler formulae are identical when they travel in a medium } \\ \text{The situation mentioned are not identical physically }\\ \text{All of the above} \end{array} $