List-I and List-II
| List-I | List-II |
|---|---|
| (A) Brundtland Report | (I) 1992 |
| (B) Antarctic Treaty | (II) 1991 |
| (C) Antarctic Environmental Protocol | (III) 1959 |
| (D) Earth Summit in Rio de Janeiro | (IV) 1987 |
Fill in the blank with the correct option.
The teacher believed that the student’s sudden lack of interest in class was an ..........., as he had always been enthusiastic and attentive.