What part of the microscope is used to move an objective lens into place?

The ocular micrometer has no units. Revolving Nose Piece - Several objective lenses of varying magnification and numerical aperture are mounted on the revolving nosepiece. The nosepiece must click into place for the objective lens to be in proper alignment.

you must remain stopped until the stop signal is retracted and the red lights are turned off. approaching traffic in the opposite roadway of a divided highway shall not be required to stop, even if the school bus has the stop-arm extended and the alternately flashing warning signal lamps on.

i might be wrong but i think its a. let me know if i’m right and have a good rest of your day!