To solve the analogy NEGI : MVTR :: SING : ?, we need to determine the pattern or rule applied to transform "NEGI" into "MVTR" and apply the same to "SING."
Thus, the word that replaces the question mark is: RTAN.
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.