. Which of the following is true'? A: . a compulsory VHF-DSC radiotelephone installation must be daily tested without radiation. B: a compulsory VHF-DSC radiotelephone installation must be annually tested without radiation C: a compulsory VHF-DSC radiotelephone installation must be monthly tested without radiation. D: a compulsory VHF-DSC radiotelephone installation must be weeklv tested without radiation.