Answer:
D: a schema.
Explanation:
Schema can be defined as a network of knowledge, beliefs, and expectations. They are largely automatic, hence, they require little attention.
Schema is created for the following reasons;
1. As a means to organize our knowledge.
2. To assist us in recalling.
3. It aids in simplifying reality.
4. Create predictions.
5. Establishes expectations in what will occur.
Dr Tranh having the expectations that the students should take note and ask question, and having made it a routine is a typical example of schema.