Answer:
a
Step-by-step explanation:
In a compound microscope, if a bacterium moves to the right, the bacterium on the slide, in reality, moved to the left.
This is because the optical system of the compound microscope is designed in such a way that the lenses change the orientation of the image of objects when viewed.
The system of two lenses - the objective and the eyepiece - produce inverted images of objects on slides. Hence, when an object on the slide under the compound microscope moves to the right, it is seen as moving to the left to the viewer and when it moves up, it is seen as moving down by the viewer.
The correct option is, therefore, a.