Answer:
A) Prepathogenesis.
Step-by-step explanation:
Prepathogenesis is the period preliminary to onset of disease.
For a disease to occur 3 factors are required.
1) Agent
2) Host
3)Environment
In absence of any of them disease cannot occur.
During prepathogenesis phase , man is not involved but he is exposed to risk of disease. During this phase the three factors (Agent , host ,environment) are present but in isolation forms. When these start interacting with each other man moves into pathogenesis phase.
Hence the answer to above question is A) Prepathogenesis.