In the regulator circuit of fig. below Vz = 12 V, β = 50,

In the regulator circuit of fig. below V_z = 12 V, β = 50, V_BE = 0.7 V. The Zener current is:

V₀ = V_Z – V_BE
= 12 – 0.7 = 11.3 V
V_CE = 20 – 11.3 = 8.7 V
Current in 220 Ω resistor is

I_{220 Ω} =	20 – 12	= 36.4 mA
	220

Current in 1 kΩ resistor is

1_1kΩ =	V₀	=	11·3	= 11.3 mA = I_C
	1 kΩ		1 kΩ

I_B =	I_C	=	11·3	= 0.226 mA
	β		50

KCL at node A, we get
I_Z = I_{220 Ω} – I_B = 36.4 – 0.226 = 36.17 mA
Hence alternative (B) is the correct choice.