What feature allows a multi-meter to measure both current and voltage?

Answer: C — Multi-function capability

The correct answer is multi-function capability, which is essential for a multi-meter to measure both current and voltage. Multi-meters are designed with the ability to switch between different modes, allowing users to measure electrical characteristics including voltage (both AC and DC) and current (again, both AC and DC), among other things like resistance and continuity. This multi-function capability is made possible by internal components that enable the meter to adjust its measurement method based on the selected function. For instance, when measuring voltage, the multi-meter uses a high-impedance input to avoid loading the circuit, ensuring that the voltage measurement is accurate. When measuring current, the device is set to a low-impedance mode, often requiring the circuit to be interrupted so that the current flows through the meter. This versatility is what makes multi-meters invaluable tools for technicians working with electrical systems. Other features, such as probes and a digital display, are important components of a multi-meter but do not inherently provide the measuring capabilities. Probes are used to make contact with the circuit for measurement, while a digital display shows the measured values. A battery indicator merely informs the user about the current battery status and does not influence the measurement features.