Correct Answer: June 5th

Solution : The correct option is -  June 5th.

Every year on June 5, the United Nations observes World Environment Day to promote environmental protection. It serves as the main United Nations environmental outreach day and is supported by a wide range of enterprises, governments, and non-governmental organizations. At the Stockholm Conference on the Human Environment, the United Nations established World Environment Day in 1972. World Environment Day is a global platform that gives companies, non-governmental organizations, communities, governments, and celebrities a theme and a platform to highlight environmental problems.