The correct answer is: no article.
The word “apple” is a common noun, which means it refers to a general class of things. Common nouns are not usually preceded by articles.
In this case, the speaker is not referring to a specific apple, but rather to apples in general. They are expressing a general desire to eat apples, not a specific desire to eat one particular apple.
If the speaker were referring to a specific apple, they would use an article. For example, if they said “I want to eat the apple that is on the table,” they would be referring to a particular apple that is located in a specific place.
In summary, the correct answer is “no article” because the word “apple” is a common noun and the speaker is not referring to a specific apple.