Find the value of Norton resistance at the terminals a-b for the circuit shown here.(where V = 10 V, I = 5 A, R1 = 9 Ω, R2 = 18 Ω, R3 = 4 Ω)

Find the value of Norton resistance at the terminals a-b for the circu

1.	Find the value of Norton resistance at the terminals a-b for the circuit shown here.(where V = 10 V, I = 5 A, R1 = 9 Ω, R2 = 18 Ω, R3 = 4 Ω)
A.	50 Ω
B.	25 Ω
C.	10 Ω
D.	20 Ω
Answer» D. 20 Ω