Which of the following statements is not true for biosensors?

• A. Biosensors convert a biological signal into an electrical signal
• B. Biosensors are used to determine the concentration of substances and other parameters of biological interest even where they do not utilize a biological system directly
• C. Biosensors utilize the different biological systems such as enzymes, whole cell metabolism, ligand binding and the antibody-antigen reaction
• D. Biosensor consists of a vessel, or series of vessels, used to perform a desired conversion by enzymic means