A demonstration is an act of showing by giving proof or . . . . . . . . evidence. A. a B. an C. the D. no article

The correct answer is D. no article.

A demonstration is an act of showing by giving proof or evidence. It is not necessary to use an article before the word “evidence” in this context.

The other options are incorrect because they are all articles. An article is a word that is used to modify a noun. In this case, the noun is “evidence.” 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 case, the noun “evidence” is not specific or unique, so it does not require an article.