The correct answer is B) primary coil. When the primary winding of a voltage transformer is connected to a steady DC source, there will be no self-inductance or mutual inductance in the transformer. However, the primary coil will still experience a current overload. This is because with a DC source, the impedance of the primary coil is essentially just the resistance of the coil winding, which is typically very low. As a result, a very high current will flow through the primary coil, potentially leading to overload and damage. The other options are incorrect because the secondary coil, core, and contacts are not the primary components affected by the lack of inductance in a DC-fed transformer.