An AC voltage source with an internal impedance $$Z_{1}$$ is connected to a load of impedance $$Z_{2}$$ . For maximum power transfer to the load, the condition is

A

$$\mid Z_2 \mid = \mid Z_1 \mid$$

B

$$ Z_{2}=Z_{1}$$

C

$$Z_2^* = -Z_1$$

D

$$Z_2 = Z_1^*$$