4. Determine which five of the following seven transfer functions correspond to any of the below unit step responses A-E. Justify your selection by evaluating the responses in terms of DC gain, natural frequency, damping ratio, time constant and stability (whichever is appropriate). G1(s) = 0.1 s+ 0.1 G2(s) = 4 82 +28+4 0.5 -0.5 G3(s) = G4(8)= $2 -0.18+2 82 +0.18 +2 1 4 G5 (8) = G6(s) = S+1 2 s² + 0.88 +4 G7 (8)= = s² + s +3 y 1 y 1 A C 1 1 t y 1- y 1 1 t 1 B D t t