When fire detecting systems, fire extinguishing systems, and associated equipment are not required by the Coast Guard but are installed on a cargo vessel at the option of the vessel's owner, they __________.

Correct Answer: Option C — must also be inspected and/or tested in accordance with Coast Guard Regulations at each Inspection for Certification

46 CFR 91.25-1 stipulates that any fire detecting or extinguishing equipment installed on a vessel, even if not required by regulation, must be maintained in good working order and is subject to inspection and testing during the vessel's Inspection for Certification to ensure overall maritime safety standards are met.