Based on the shape, bacterial cells can be coccus (spherical), bacillus (rod-shaped), spirilla (spiral), vibrio (comma-shaped), etc. Vibrio cholerae is a comma-shaped bacterium which causes cholera. The major symptom of cholera is severe diarrhoea with subsequent water loss from the body. If the patients are not treated well and their water loss is not compensated, they can suffer from severe dehydration.

Microbial diseases that spread from an infected person to a healthy person through air, water, food or physical contact are called communicable diseases or infectious diseases. Malaria, measles and  some respiratory illnesses are examples of infectious diseases.

Sodium chloride (common salt), acids like sodium benzoate and sodium metabisulphite are commonly used food preservatives. Sodium lauryl sulphate (SLS) is a detergent usually present in shampoo.

Fungi are responsible for various diseases in human beings. Ringworm is a common fungal skin infection that often looks like a circular rash. In the given options, chicken pox is a viral disease, while cholera and tuberculosis are bacterial in origin.
The given image depicts a person with ringworm.

Answer: Option A. ->

Chlamydomonas:

This is Chlamydomonas, a type of algae. They are found in stagnant water,freshwater,seawater etc.
Amoeba:

This is an irregularly shaped protozoan called amoeba. 
Aspergillus:

This is a fungus belonging to the genus Aspergillus.
Penicillium:

This is a fungus belonging to the genus Penicillium.

Based on the shape, bacterial cells can be coccus (spherical), bacillus (rod-shaped), spirilla (spiral), vibrio (comma-shaped), etc. Vibrio cholerae is a comma-shaped bacterium which causes cholera. The major symptom of cholera is severe diarrhoea with subsequent water loss from the body. If the patients are not treated well and their water loss is not compensated, they can suffer from severe dehydration.

Fungal species such as Penicillium, Aspergillus, etc. and many bacterial species are often found dwelling in colonies. On the contrary, protozoans like amoeba and paramecium are found living independently.