K-initial three-letter progressive groups – UGC NET Question

In this series, the first letter K remains fixed while the second and third letters move forward by two positions each time. The second letters L, N, P and R are at positions 12, 14, 16 and 18, and the third letters M, O, Q and S are at positions 13, 15, 17 and 19. Continuing this plus two progression, the next second and third letters should be T (20) and U (21), giving KTU.

Option A:
Option A, KUV, uses U and V for the second and third letters, which would be four positions ahead of R and S. This doubles the required step size and breaks the consistent plus two movement. As such, KUV does not conform to the series rule.

Option B:
Option B, KST, sets S and T in the second and third positions, which are only two and three positions ahead of R and S collectively. This creates unequal shifts and does not follow the clear parallel movement of both letters by two. Therefore KST is not an accurate continuation.

Option C:
Option C is correct because T and U are exactly two positions beyond R and S respectively, maintaining the same parallel increase. The first letter K is unchanged, reflecting the fixed initial position, and the second and third letters move in lockstep. This makes KTU the logical extension of the pattern.

Option D:
Option D, KTV, advances the second letter correctly to T but moves the third letter to V, which is three positions after S. This lack of parallelism in the movement contradicts the even shifting behaviour found in the series. Consequently, KTV cannot be chosen as the next term.