Parenthetical citations generally include the letter p. and a page number the author's last name and a page number the author's last name, the letter p., and a page number the author's last name, a comma, and a page number

The correct answer is option b. Parenthetical citations generally include the author's last name and a page number.

Explanation:

Parenthetical citations within the text let the reader know when the author have used information from another source. From every in-text citation there must be a corresponding entry in the works cited list. The parenthetical citation style uses the author's last name and the page number; for example: (Roberts 108)