In the given circuit, the current through zener diode is:

the current through 500 ohm resistor is 0.01 ampere as voltage across is 5V. the current through 1500 ohm resistor is 0.0067 ampere so the current through zener diode is difference in current through these resistors . so the current is 0.01 - 0.0067 = 0.0033 ampere . On converting to mA we get Current through zener diode = 3.3 mA so the correct answer is B.