For a two-port, let A = 4, B = 30 , C = 0.1 S, and D

For a two-port, let A = 4, B = 30 Ω, C = 0.1 S, and D = 1.5. Calculate the input impedance, Z11 = V1 / I1 in when:
(a) The output terminals are short-circuited,
(b) The output port is open-circuited,
(c) The output port is terminated by a 10 - Ω load.