Final answer:
The visibility of mottle in the virtual image is determined by resolution, sensitivity, and contrast level.
Step-by-step explanation:
The visibility of mottle in the virtual image is determined by all of the above in the system in use, which includes resolution, sensitivity, and contrast level.
Resolution refers to the ability to distinguish separate points or objects, and higher resolution images appear sharper. Sensitivity relates to the system's ability to detect and interpret subtle differences in the image. Contrast level determines the difference in brightness between different parts of the image.
Therefore, all of these factors play a role in determining the visibility of mottle in a virtual image.