Which of the following is primarily a malt-derived flavor?

Malt-derived flavors are a key aspect of beer and are primarily influenced by the grains used in the brewing process. Caramel is a sweet, rich flavor often associated with malt, particularly from caramel or crystal malts. These malts undergo a specific process that includes kilning, which develops the sugars and leads to the formation of caramel flavors through the Maillard reaction during roasting.

In contrast, citrus flavors typically come from hops, which are added for bitterness and aroma and contribute to the fresh, zesty notes found in certain beer styles. Green tea flavors might hint at specific ingredients or adjuncts used in brewing rather than being directly linked to malt characteristics. Sugar beets, while they may contribute sweetness, are not derived from malt and are not typically found in the flavor profile of traditional beers.

Thus, caramel distinctly represents a flavor that originates from the malt, making it the correct choice in this context.