An inductor of reactance 1 Ω and a resistor of 2 Ω

An inductor of reactance 1 Ω and a resistor of 2 Ω are connected in series to the terminals of a 6 V (rms) a.c. source. The power dissipated in the circuit is

(a) 8 W.

(b) 12 W.

(c) 14.4 W.

(d) 18 W.