What vegetable can be sweet or spicy?

A pepper is the correct answer because it encompasses a wide variety of types that can range from sweet to spicy. For instance, bell peppers are generally sweet and mild, making them a popular choice in salads and stir-fries. On the other hand, varieties like jalapeños, habaneros, and ghost peppers have varying heat levels, providing the spicy kick in many dishes. This versatility in flavor is what distinguishes peppers from other vegetables in the options provided.

While garlic, tomatoes, and onions each have distinct flavor profiles, they do not typically present the same range of sweetness versus spiciness as peppers do. Garlic has a strong, pungent flavor, tomatoes are primarily sweet or tangy, and onions have a sharp taste that can be sweet when caramelized but do not provide the same heat that some peppers do. Therefore, the broad spectrum of flavors in peppers makes them the definitive choice for a vegetable that can be sweet or spicy.