When asked about his favorite book, he replied, "My favorite book is To Kill a Mockingbird" and then proceeded to explain why.
Correct: A
When a direct quotation is introduced by a verb like 'replied', a comma typically precedes the opening quotation mark. If the quotation is part of a larger sentence and is not a complete sentence on its own in the context of the main sentence, a comma should follow the closing quotation mark before continuing the main sentence. The period goes inside the quotation marks only if the quote ends the sentence. Here, the quote is integrated into the sentence. Option A correctly places a comma before the opening quote and a comma after the closing quote to connect it to the rest of the sentence. The period should be inside if the quote ends the entire sentence, but here it's followed by 'and then proceeded'.