The correct answer is D. no article.
The word “honest” is an adjective that describes a person who is truthful and fair. It is not a noun, so it does not require an article.
The other options are incorrect because they are all articles. An article is a word that is used to introduce a noun. In this case, the noun is “person.” The articles “a” and “an” are used before singular nouns that begin with a consonant sound. The article “the” is used before singular nouns that are specific or unique.
In this sentence, the word “person” is not specific or unique. It could refer to any person, so it does not require an article.