Punctuating a Dependant and an Independent Clause
One of the most common opening frames is an author tag or attribution such as, "According to Howard Sprague, an accountant with…" or, "As President Clinton said in his first inaugural speech…."
By themselves neither is a complete sentence. We are left waiting to hear what was according to Mr. Sprague and what was said by President Clinton. As opening frames they are dependant upon the quotes they precede.
When the opening frame is a dependant clause, such as an author tag, and the following quote is an independent clause the two may be separated by a comma or a colon, depending upon the length of the quote, as in Examples A and B.