Which of the following is an expository teaching method where the teacher directly explains concepts in a teacher-centered classroom?
Lecture
Expository (didactic) teaching methods are teacher-centred, where the teacher directly presents or explains information to students who largely play a receptive role.
The lecture method is the clearest example of this: the teacher verbally explains concepts in a structured, one-way manner while students listen and take notes.
Discussion and role play are learner-centred, participatory methods, while the project method is activity-based and learner-driven, so none of these fit the expository, teacher-centred description.
Therefore, the correct answer is Lecture.