Not ... likes onions.

This is a multiple-choice question. The sentence is "Not ... likes onions." We need to choose the word that best fits the blank to make a grammatically correct and logical sentence.

• If we choose 'everyone': "Not everyone likes onions." This means that some people like onions, but not all of them do. This is a common and logical statement.
• If we choose 'anyone': "Not anyone likes onions." This means that absolutely no one likes onions. This is a very strong statement and less likely to be true in a general context. 'Anyone' is often used in negative sentences to mean 'no one', but 'everyone' is more natural here when implying a partial group.

Therefore, 'everyone' is the most appropriate choice.

Answer: everyone