The best answer to the question "The Green party is popular throughout the world and promotes eco-friendly policies" is "OF."
Explanation:
1. "OF" indicates possession or association. In this context, it shows that the eco-friendly policies are associated with the Green party.
2. The sentence highlights that the Green party is well-liked globally and advocates for environmentally friendly practices.
3. By choosing "OF," it emphasizes the relationship between the Green party and the eco-friendly policies it supports.
Therefore, the most suitable choice to complete the sentence is "OF," as it correctly reflects the connection between the Green party and its environmental agenda.