Answer:
III, II, I and IV
Step-by-step explanation:
The correct order of application of Koch's postulate is as following
III. Find suspect agent is every case of disease of interest but not in healthy hosts,
II. Isolate and culture suspect agent in the laboratory.
I. Inoculate suspect agent into test subject and observe that subject develops disease of interest.
and
IV. Recover and isolate suspect agent from test subject.
that is III, II, I and IV