During a Social Studies Lesson on the Drafting of the Constitution

During a Social Studies lesson on the drafting of the Constitution, Ms. Agis notices that many of her students are losing attention. She feels that it is important for her students to understand the process that brought about the final version of the Constitution. She opts to use a form of extrinsic motivation that will bring attention back and make her students want to participate in the learning. An appropriate form of extrinsic motivation would be which of the following?

A) Reminding students that their grades will be affected by their non-participation
B) Telling her poor performers that there grades will improve if they keep focus
C) Offering her student a pizza party at the end of the unit if all students finish all assignments
D) Organizing more group work to make the unit more student-directed