In the scenario, Maurice is involved in making her students physically ready to listen. Option A.
The focus of every teacher (a science teacher at that) is to ensure the maximum, undivided attention of his or her students. While students have their personal stuffs, they tend to lose focus and not concentrate on what is been taught.
The act of instructing the students to keep their belongings in their bags is to eliminate every form of distraction from them, which will invariably prepare them for listening and learning.
Listening doesn't deal with hearing alone. It entails paying rapt attention to what is been said or discussed.