Two wattmeter method is employed to measure power in a 3-phawe balanced system with the current coil connected in the A and C lines. The phase sequence is ABC. If the wattmeter with its current coil in A-phase line reads zero, then the power factor of the 3-phase load will be
1. Zero lagging
2. Zero leading
3. 0.5 lagging
4. 0.5 leading