Answer:
C. Millimeter
Explanation:
A microscope is a measuring device. Least count and small count are not scale divisions they are not accurate which only leaves you with millimeter which is an actual scale division.
An orchestra is defined as a large instrumental ensemble typical of classical music. An orchestra features bass, brass, strings, woodwinds, and percussions. In the list given above, the section that is not one of the four groups in the orchestral palette is the voices. The answer would be "voices".