What instrument is specifically used for measuring electrical resistance?

The instrument specifically designed for measuring electrical resistance is the ohmmeter. This device operates on the principle of measuring the voltage drop across a resistor and calculates the resistance using Ohm's law (R = V/I). Ohmmeters are calibrated to display this resistance value directly, enabling accurate determination without needing additional calculations or configurations.

While other choices may measure aspects of electrical systems—such as voltage with a voltmeter, current with an ampermeter, or both voltage and current with a multimeter—they do not specialize in measuring resistance. The multimeter can indeed measure resistance, but it is a more general-purpose tool that includes multiple functions, making the ohmmeter the most precise and direct choice for measuring electrical resistance specifically.