Regarding this array: Mr. Ortiz plans a variety of activities for the students to participate in during an upcoming unit. This shows that Mr. Ortiz knows that effective instruction ________.

A. always includes a written test at the end of a unit.
B. means to have plenty of group work rather than instructional lessons because the students will entertain themselves with activities.
C. incorporates an assortment of activities to increase student engagement and motivation.
D. should include products made by small groups so there are fewer products to grade.