The correct answer is D) All of the above must be tested. When a new Master assumes command of a vessel, all installed equipment, including vessel control alarms, navigational lights and searchlights, and internal communications systems, must be tested and the results logged. This is a requirement under the U.S. Coast Guard regulations for maintaining proper safety standards and ensuring the vessel is fully operational under the new Master's command. The other answer choices are incorrect because they do not encompass the full scope of required testing that must be completed.