How many pieces of candy did Omar and Marcos leave?

The correct answer indicates that Omar and Marcos left a small number of candy pieces, which is what "a few" conveys. This phrase suggests a quantity that is more than one but relatively small, typically understood to mean two to three items in casual conversation.

Using "none" would imply that they left nothing behind, which contradicts the choice indicating they left some candy. "A little" generally refers to an uncountable amount, such as liquid, and does not apply to countable items like pieces of candy. "Several" suggests a larger quantity than "a few," typically meaning more than three, which might not align with the information provided regarding their actions. Therefore, "a few" correctly captures the idea that they left some quantity of candy without specifying an exact number, making it the most suitable choice in this context.