ANS:B - anodic protection.

Galvanic corrosion can not be prevented by anodic protection. Explanation: Galvanic corrosion occurs when two dissimilar metals are in electrical contact with each other in the presence of an electrolyte (such as moisture or saltwater). In this electrochemical process, one metal acts as the anode and corrodes, while the other metal acts as the cathode and remains protected. Cathodic protection works by making the metal to be protected the cathode in the electrochemical cell, effectively preventing it from corroding. This is achieved by supplying a sacrificial anode (a more reactive metal) or by impressing a direct current to polarize the protected metal cathodically. Anodic protection, on the other hand, attempts to protect the metal by making it the anode in the electrochemical cell. This involves controlling the potential of the metal to be protected at a level where it does not corrode. However, anodic protection is not effective in preventing galvanic corrosion, as it would require the metal to be actively corroded, which is counterproductive. Therefore, anodic protection cannot prevent galvanic corrosion, and the correct answer is anodic protection.