The correct answer is B) Clean the glass surrounding the individual navigation lights as needed. The reasoning for this is that navigation lights on vessels are critical safety equipment, and it is important to ensure they are functioning properly. The glass surrounding the lights needs to be kept clean in order to maintain the proper illumination and visibility of the lights. This is a regular maintenance task that should be performed as needed, rather than on a fixed schedule like the other options provided. The other answer choices are incorrect because they do not accurately reflect the proper maintenance requirements for navigation light circuits. Changing fuses monthly, filing buzzer contacts, and taking megger readings are not typical maintenance tasks for these types of circuits.