Its A, if you are taking the Penn Foster exam in Assignment 2 it specifically says, "In MLA style, you use parenthetical citation to refer to the works of others in your own work."
This is called parenthetical citation because you use parentheses ( ) to cite the source. The parenthetical citation is found after the information that needs to be cited. It includes the author's last name and page number if needed. If there is n author, it includes the title of the source. The other options are just words that start with p and end in 'al'.
