The correct answer is C. beverage.
A beverage is a liquid that is typically consumed to quench thirst. It may be hot or cold, and it can be made from a variety of ingredients, including water, milk, juice, tea, coffee, and soda. Beverages can be alcoholic or non-alcoholic.
In the context of the question, the friend is saying that he drinks tea because it is the best beverage in the world. This means that he believes that tea is the best drink to quench thirst, and that it is the best drink overall.
The other options are not as accurate. A fluid is a substance that can flow, and it can be either a liquid or a gas. A drink is a liquid that is typically consumed to quench thirst, but it can also refer to a non-liquid beverage, such as a smoothie. A liquid is a substance that has no fixed shape and takes the shape of its container.
I hope this helps!