Answer:
b. unicellular prokaryotes
Explanation:
Most of the bacteria are primitive organisms that is why they are not very advanced in terms of cellular organelles and body functions. They do not have high level of organization in their body like presence of tissues, organs, organ systems etc. because they are only single celled organisms that is why they are known as unicellular organisms. A single cell performs all the functions required to sustain life. Their genetic material is very primitive type of structure which does not have any nuclear membrane or nuclear envelop. It is circular in shape and lies in the cytoplasm and it is known as nucleoid instead of nucleus.
For example: E. coli.
