An ac source of voltage \(\rm E_S\) and an internal impedance of \(\rm {Z_{th}} = \left( {{R_S} + j{X_S}} \right)\) is connected to a load of impedance \(\rm {Z_L} = \left( {{R_L} + j{X_L}} \right)\). Consider the following condition in this regard.1. \(\rm {X_L} = {X_S}\) if only \(\rm X_L\) is varied2. \(\rm {X_L} = - {X_S}\) if only \(\rm X_L\) is varied3. \(\rm {R_L} = \sqrt {R_S^2 + {{\left( {{X_S} + {X_L}} \right)}^2}} \), if only \(\rm R_L\) is varied4. \(\rm \left| {{Z_L}} \right| = \left| {{Z_S}} \right|\) If the magnitude alone of \(\rm Z_L\) is varied, keeping the phase angle fixed.Among these conditions, those which are to be satisfied for maximum power transfer from the source to the load would include

• A. 2 and 3
• B. 1 and 3
• C. 1, 2 and 4
• D. 2, 3 and 4