Correct option is (c) \(\frac{2\pi}{M}\)(k+α)
Easiest explanation: To derive the frequency sampling structure, we specify the desired frequency response at a set of equally spaced frequencies, namely ωk=\(\frac{2\pi}{M}\)(k+α), k=0,1…(M-1)/2 for M odd
k=0,1….(M/2)-1 for M even
α=0 or 0.5.