In the circuit given below, assume that $$V_{cc}= 15V; Z_{1}, Z_{2}, Z_{3} \& Z_{4}$$ are identical zener diodes with breakdownvoltage of 5V; $$R_{1} = R_4 = 5kΩ, R_{2} = R_{3} = 10kΩ$$. Find $$V_{o}$$ when $$Q_{1}$$ is OFF.

A

7.5 V

B

5 V

C

10 V

D

8.33V