Final answer:
The kingdom in the five-kingdom classification system whose organisms are prokaryotes is Monera. Prokaryotes are unicellular and lack a nucleus and other membrane-bound organelles. The option (B) is correct.
Step-by-step explanation:
Using the five-kingdom system of classification, the kingdom whose organisms are prokaryotes is Monera. The organisms in the Kingdom Monera (also referred to as Bacteria in some classifications) are primarily unicellular and lack a defined nucleus and other membrane-bound organelles, which are characteristic features of prokaryotic cells. In contrast, the Kingdoms Protista, Fungi, Animalia, and Plantae all consist of eukaryotes, whose cells contain a nucleus and organelles enclosed within membranes.
As an example, E. coli, a well-known bacterium, is a member of the Kingdom Monera and is a prokaryote. The term prokaryote refers to unicellular organisms that do not have a nucleus or other membrane-bound organelles. Therefore, option (B) is correct.