Quotation marks are used to indicate material that is being reproduced word for word. Quotation marks must begin and end with the direct speech.
According to these rules, Option A can be termed wrong, as it encloses the whole sentence within quotes. The correct answer is Option B.
Option C is incorrect as, commas and periods that are part of the original sentence go inside the quotation marks, even though they are not part of the original quotation.
Option D is incorrect, the direct speech is not enclosed within quotation marks.