Why could old human teachers give children the habit of learning in groups?

Correct answer: Because they encouraged discussion and participation in class

The governing idea is that education is not only the transfer of information; it is also a social activity. In an old-style classroom, one human teacher could ask questions, invite several children to answer, arrange shared tasks, and respond to their different ideas. Such repeated discussion and cooperation naturally trained students to listen, speak, help one another, and learn as a group. Therefore, option A is correct because it directly explains how group-learning habits could develop. Options B, C, and D contradict this idea: separation prevents cooperation, a teacher did not become a machine, and giving no lessons could not create a learning habit.