Measurement of power and power factor of a 3-phase system by two wattmeter method can be obtained in case of

1. Balanced load and balanced source

2. Balanced source with 3-phase 3-wire unbalanced load

3. Unbalanced source with 3-phase 3-wire balanced load

4. Balanced source with 3-phase 4-wire unbalanced load

5. unbalanced and unbalanced source

(a) 1 only (b) 2, 3 and 5 (c) 1, 2, 3, 4 and 5 (d) 1, 2, 3 and 5

1. Balanced load and balanced source

2. Balanced source with 3-phase 3-wire unbalanced load

3. Unbalanced source with 3-phase 3-wire balanced load

4. Balanced source with 3-phase 4-wire unbalanced load

5. unbalanced and unbalanced source

(a) 1 only (b) 2, 3 and 5 (c) 1, 2, 3, 4 and 5 (d) 1, 2, 3 and 5