The correct answer is (d). Ernst Haeckel coined the term “ecology” in 1866. He defined it as the study of the relationships between organisms and their environment.
Charles Elton was a British ecologist who is considered one of the founders of modern ecology. He is best known for his work on food chains and trophic levels.
Arthur Tansley was a British botanist who is considered one of the founders of the science of ecology. He coined the term “ecosystem” in 1935.
Eugene Odum was an American ecologist who is considered one of the founders of the field of ecosystem ecology. He is best known for his work on energy flow in ecosystems.