What is galvanic corrosion primarily a result of?

Galvanic corrosion is primarily the result of electrochemical action that occurs between dissimilar metals when they are in contact in the presence of an electrolyte, such as water. This type of corrosion happens because there is a difference in electrochemical potential between the metals involved. When two metals with different electrode potentials come into electrical contact while immersed in an electrolyte, one metal will act as an anode (the metal that corrodes) and the other as a cathode (the metal that is protected from corrosion).

The presence of moisture does contribute to the electrochemical process by acting as the electrolyte, but it is the interaction between the dissimilar metals that directly leads to galvanic corrosion. Exposure to sunlight and temperature fluctuations can influence environmental conditions but are not the primary cause of galvanic corrosion. The key factor here is the electrochemical action, which is why this option is the most accurate answer regarding the causes of galvanic corrosion.