The question asks about the frequency with which the World Happiness Report is released. Let's look at each option and determine the correct answer:

• Quarterly: This would mean the report is published four times a year. However, the World Happiness Report is not released this frequently.
• Annually: This is the correct option. The World Happiness Report is indeed published once every year. It is released to coincide with the International Day of Happiness on March 20th. This report assesses global happiness by ranking countries based on various factors including GDP per capita, social support, life expectancy, freedom to make life choices, generosity, and perceptions of corruption.
• Triennially: If this were the case, the report would come out every three years, which is incorrect.
• Biennially: This implies a release every two years, which is also incorrect for this report.

Thus, the correct answer is Annually, meaning the World Happiness Report is released once a year.