Explanation: Cavity resonators are specialized resonant structures used extensively at UHF and microwave frequencies. They indeed function as a form of resonant tank circuit (A), where the physical dimensions of the enclosed metallic cavity determine the resonant frequency by supporting standing electromagnetic waves, effectively replacing traditional lumped inductors and capacitors. Physically, they typically consist of a hollow metal cylinder or box closed on all sides (B), providing a conductive enclosure that traps and reflects the electromagnetic fields. Due to this construction and the confinement of fields, cavity resonators exhibit extremely low energy losses, resulting in a very high Quality factor (Q) and exceptional selectivity (C). These characteristics make them ideal for precise frequency filtering and stabilization in radio systems. Therefore, all the statements accurately describe cavity resonators.