The antibiotic penicillin is obtained from

The correct option is B

Fungus

The correct option is B:

Explanation for correct option:

1. Fungi can be single-celled organisms or multicellular organisms with a great deal of complexity.
2. They can be found in almost any habitat, but the majority of them reside on land, primarily in the soil such as yeasts, molds, and mushrooms.
3. Penicillin is an antibiotic that can be made from the fungus Penicillium notatum or Penicillium chrysogenum.
4. Penicillin is an antibiotic that inhibits the cell wall formation in the pathogenic bacteria and thereby inhibiting the growth of pathogenic bacteria.

Explanation for the incorrect options:

Option A:

1. Most of the antibiotics used in medicine are produced by bacteria.
2. Bacteria belonging to the genus Streptomyces are the major source of antibiotics.

Option C:

1. Viruses are obligate parasitic organisms that do not show any antibiotic property.
2. They do not produce any antibiotics.

Option D:

1. Protozoans are single-celled eukaryotes that cause diseases in higher animals.
2. Infections caused by protozoans may be asymptomatic or sometimes life-threatening.

Final answer: The antibiotic penicillin is obtained from fungus.