How would you determine the resolution of a measuring instrument?

The resolution of a measuring instrument refers to the smallest increment that can be measured by that instrument. This directly relates to how finely the measuring scale is divided, which is best identified by looking at the smallest unit displayed on the instrument's scale. The smaller the unit, the higher the resolution, meaning the instrument can provide more precise measurements.

In contrast, options related to examining the overall length, checking brand reputation, or testing against other instruments do not directly indicate the ability of the instrument to measure small variations. While testing against other instruments may provide context about accuracy or precision compared to a standard, it does not define the inherent resolution of the measuring device itself. Therefore, the correct approach to determining resolution is indeed based on the smallest unit marked on the scale of the instrument.