`=>` B. self-discipline 

- A : As students do more self-study, many become more self-motivated learners.

- C : Exploring a topic on his or her own encourages students to actively engage with the information.

`@` on ones own : tự ai làm ~ self (bản thân)

- D : First, self-study allows students to take learning at their own pace, focusing on areas they are most interested in.