2.3. Which of the FIR filters defined by the following impulse responses are linear phase filters?

a. h[n] = {0.2, 0.3, 0.3, 0.2}

b. h[n] = {0.1, 0.2, 0.2, 0.1, 0.2, 0.2}

c. h[n] = {0.2, 0.2, 0.1, 0.1, 0.2, 0.2}

d. h[n] = {0.05, 0.15, 0.3, -0.15,-0.15}

e. h[n] = {0.05, 0.3, 0.0, -0.3, -0.05}