Final answer:
Entomology is not a subfield of microbiology; it is the study of insects and does not involve microorganisms.
Step-by-step explanation:
The field of microbiology covers various subfields, each dedicated to the study of different types of microorganisms. For example, bacteriology focuses on bacteria, mycology is concerned with fungi, protozoology encompasses the study of protozoa, parasitology involves helminths and other parasites, and virology centers on the study of viruses. However, entomology is not a subfield of microbiology; it is the scientific study of insects and therefore does not align with the study of microorganisms. Accordingly, the correct answer to which of the following is not a subfield of microbiology is d) Entomology.