Which of the following property is not possessed by biosensors?

• A. The probe used in the biosensor must be tiny and biocompatible, having no toxic or antigenic effects
• B. The biosensor should be cheap, small, portable and capable of being used by semi-skilled operators
• C. There should be a market for the biosensor
• D. The specificity of substrate binding is mediated by spatial arrangement of atoms in an enzyme s substrate binding site as well as substrate.