The Code is built in three layers, and items move between them. A core value (C) is something the profession holds important — service, integrity, competence and the rest. An ethical principle (B) is the broad aspiration that follows from a value, and principles guide how the Code is read rather than being enforced on their own. The numbered standards are the specific rules, and they are what a licensing body acts on, which is why A is right here. The layers matter in practice: where no standard fits a situation, the values and principles above them are what you reason from.