A. Zoology is the branch of science that deals with the study of animal kingdom.
B. Ecology is the branch of science that deals with the study of interaction of organisms with each other and with their surroundings or environment.
C. Botany is the branch of science that deals with the study of plants.
D. Herpetology is the branch of zoology that deals with the study of amphibians.
So, the correct answer is 'Ecology'.