Explanation:

- The concept of ‘Ecological Transition’ refers to changes in settlement or social structures due to shifting environmental or ecological factors.

- Frederic Bennett (Option 2) was the first to use this term in human geography to describe the process when a group of people shifts to a new habitat, leading to a change in societal organization.

- Charles Elton (Option 1) is known for his work in animal ecology and food chains, not for 'Ecological Transition'.

- George Berkeley (Option 3) was an Irish philosopher and is not associated with ecology or this concept.

- Friedrich Ratzel (Option 4) is known for the concept of environmental determinism and anthropogeography, but did not use ‘Ecological Transition’ first.