Which of the following organisms are prokaryotes?
a. plants
b. animals
c. bacteria
d. fungi

Option (C)

Explanation: Prokaryotes are those organisms that does not have a well defined nucleus and the cells are known as the prokaryotic cells, whereas eukaryotes are those organisms that has well defined nucleus, whose cells are known as eukaryotic cells.

Plant, animals and fungi belongs to the eukaryotes but bacteria belongs to the prokaryotes.

Bacterias are the unicellular micro-organism that contains a prokaryotic nucleus and are helpful in the fermentation process, but also can cause infection to the animals and human bodies.

Thus, the correct answer is option (C).