This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
The microscope used in microbiology - 
Select and explain. 
A. Light microscope, B. Phase contrast microscope, C. Fluorescent microscope, D. All
D: All
Answer: D: All 
Explanation: Why is it necessary to use a microscope in microbiology?
The diameter of the smallest object that can be seen by the naked (unaided) eye is about 200U.
Most microorganisms are smaller than this and therefore, they should be sufficiently magnified before study.
For this purpose various types of microscopes are available.
Types of microscopes 
A) Visible light as a source of illumination

Bright-field microscope, commonly known as a light microscope or optical microscope.
Darkfield microscope
Phase contrast microscope

B) UV rays as a source of illumination

Fluorescence microscope

C) Electron beam forms image of specimen

Electron microscope

D) Surface forces form image of specimen

Atomic force microscope (AFM)