Restriction enzymes are isolated chiefly from.
A. Algae
B. Fungi
C. Protozoa
D. Prokaryotes

Hint: A restriction enzyme or restriction endonuclease or restrictase is an enzyme that cleaves DNA into fragments or near specific recognition sites within the molecules known as restriction sites. Restriction enzyme is nothing but the enzyme produced by certain bacteria that have the ability to cleave DNA molecules at a specific sequence. These are isolated from bacteria.

Complete answer:
Option A algae: Algae is a diverse group of aquatic organisms; they have the ability to conduct photosynthesis. Most algae require moist or water environments. Algae can be either unicellular or multicellular. But they lack a wee-defined body like root, stem or leaves.
Option A is incorrect
Option B fungi: Fungi includes many organisms like yeast, mold, smuts, rusts and mushrooms. Fungi are among the most widely distributed organisms in the world. Many fungi are free living in the soil or water, others depend on other organisms like parasites or symbiotics.
Option B is incorrect.
Option C protozoa: Phylum or a phyla grouping comprising single cell microscopic animals, including amoeba, flagellates, ciliates, sporozoans, and many other animals. They are the eukaryotic body group.
Option C is incorrect.
Option D prokaryotes: These endonucleases facilitate the particular fragmentation of double-stranded DNA and are useful in the analysis of the DNA sequence. These enzymes can be divided into three different groups. Enzymes type I and type III are modified (methylated) and ATP are restricted (cleavage) in the same protein. In DNA, however, both types of enzymes can identify mono methylated sequences but randomly cleave Type I enzymes, and in specific sites Type III enzymes can cleavage DNA. The limitation enzyme of Type II comprises a separate endonuclease restriction and a methylase modification. The limiting enzyme was therefore mainly isolated from the prokaryotes.

Option D is correct.

Note:
The restriction enzyme is isolated chiefly from the prokaryotes, which recognises specific nucleotide sequences within the double standard DNA and cleaves it at these sites. The bacteria will use the restriction enzyme to defend against a bacterial virus called bacteriophage. These restriction enzymes were discovered in late \[1960\]’s and early \[1970\]’s.