Answer :
Answer:
Immunologist - studies ecology of Legionella pneumophila.
Explanation:
The field biology mainly deals with the study of the living organisms. Biology includes the different sub field like ecology, immunology, cell biology, molecular biology and biotechnology.
The immunology is the field of biology that mainly deals with the antigen- antibody interaction and detailed study of the immune system of the living organisms. The immunologists studies about immunology and not the ecology of the organisms.
Thus, the correct answer is option (A).