Which punctuation mark is used to introduce a quotation?

Using a colon to introduce a quotation is appropriate when you're presenting a quotation that is preceded by a complete sentence or when the quoted material is formal or particularly significant. For example, if you have a statement like, "The author emphasized an important point:" followed by a direct quote, the colon indicates that what follows is a direct elaboration or citation related to the previous statement.

It's essential to recognize that while commas are often used to introduce quotations, particularly when it follows a phrase leading directly into the quote, the question specifically highlighted the scenario suited for a colon, where a more formal introduction is warranted. The apostrophe is primarily used for possession or to form contractions, not for introducing quotations. Similarly, the semi-colon serves a different grammatical purpose, linking independent clauses rather than introducing forthcoming statements.