Which of the following tools is best for measuring resistance in a circuit?

The correct option is the ohmmeter, which is specifically designed for measuring electrical resistance in a circuit. Resistance is measured in ohms, and the ohmmeter provides a direct reading of how much resistance exists. This tool typically has its own internal battery, allowing it to apply a small voltage to the circuit being tested. The resulting current flow can then be used to calculate the resistance based on Ohm's Law (V=IR).

While a multimeter can also measure resistance, it is a more versatile tool that can serve multiple purposes, including measuring voltage and current. However, when asking for the best tool specifically for measuring resistance, the ohmmeter is the more specialized choice. It is dedicated solely to this task, offering precise readings without the need for additional configurations that a multimeter might require.

An ammeter measures current flowing through a circuit, while a voltmeter measures voltage. Neither of these tools is used for resistance measurement. Thus, the best answer for measuring resistance in a circuit is clearly the ohmmeter.