Explanation:

- "Living Planet Report" is published by the World Wide Fund for Nature (WWF).

- Correct Answer: Option 4 - World Wide Fund for Nature

- The WWF is a leading global conservation organization known for its work to protect nature and reduce the most pressing threats to biodiversity.

- Option 1: United Nations Environment Programme is responsible for coordinating the UN's environmental activities and assisting developing countries in implementing environmentally sound policies.

- Option 2: Intergovernmental Panel on Climate Change (IPCC) is focused on climate change science, evaluations, and assessments but doesn’t publish the Living Planet Report.

- Option 3: United Nations Educational, Scientific and Cultural Organization (UNESCO) primarily deals with educational, scientific, and cultural collaboration worldwide.