Finland was ranked the happiest country in the world, as of March 2020. World Happiness Report is published annually by:

Correct option is C

The correct answer is (C)  United Nations Sustainable Development Solutions Network (UNSDSN)

• ​The World Happiness Report is published every year by the United Nations Sustainable Development Solutions Network (SDSN).
• It measures and ranks the happiness levels of people in more than 150 countries based on how satisfied they feel with their lives.​