The sensitivity of a system is defined as:

The sensitivity of a system refers to its ability to detect small changes in input or output values. This characteristic is crucial in control systems as it determines how responsive the system is to slight variations, which can be vital in ensuring precision and accuracy in measurements and controls. A system with high sensitivity can detect even minute fluctuations, allowing for more effective adjustments and control actions.

The other options address different aspects of system performance but do not define sensitivity directly. For instance, response time involves the speed at which a system reacts but does not relate to its ability to detect changes. The maximum value in a range pertains to the limits of measurement capabilities rather than sensitivity itself. Lastly, accuracy involves how closely a measurement aligns with the true value but does not specifically indicate the system's capability to perceive small changes.