Answer: C. Student discussions
Step-by-step explanation:
Student discussions is the only activity that directly involves students needing to interact with other students, therefore it is an active participation activity. Reading a book is better suited to quite and independent activities, watching a video also requires students to become quite and pay attention, same for listening to an audio clip and attending lectures. While these activities can be made active, much of that activity would come from them talking with each other about what they read, saw, or heard, which all fall under the umbrella of student discussions.