Choose the correct statement regarding two watt-meter method for power measurements in 3-phase circuit.

• A. When power factor is unity, one of the wattmeters reads zero
• B. When the readings of the two watt-meters are equal but opposite sign, the power factor is zero
• C. Power can be measured using two watt-meter method only for star connected 3-phase circuit
• D. When two watt-meters show identical readings, the power factor is 0.5