In the triplet series CAL, AWF, YSZ, WOT, which of the following three letter groups should come next to extend the alphabet pattern correctly?

Introduction / Context:
This series question involves three letter groups where each position in the triplet moves independently through the alphabet using negative steps of different sizes. It tests your ability to track multiple backward sequences and to apply modular thinking about the alphabet. Such multi position patterns are very common in advanced alphabet test sections in reasoning examinations.

Given Data / Assumptions:
- Given series: CAL, AWF, YSZ, WOT, ? - Each term is a three letter triplet. - All letters are capital English letters. - The pattern is consistent and typically made of fixed backward steps.

Concept / Approach:
We separate the series into sequences of first letters, second letters, and third letters. Each sequence is analysed numerically by converting letters to positions from 1 to 26. The differences between successive terms are computed, and we look for a constant negative step that may involve wrap around (for example from A moving backward to Z). Once we identify these consistent sub patterns, we can compute the next position in each sequence and reconstruct the next triplet in the series.

Step-by-Step Solution:
Step 1: Convert the letters to numeric positions. CAL: C (3), A (1), L (12). AWF: A (1), W (23), F (6). YSZ: Y (25), S (19), Z (26). WOT: W (23), O (15), T (20). Step 2: First letters sequence: C, A, Y, W. Positions: 3, 1, 25, 23. From 3 to 1: -2. From 1 to 25: when we step back 2 positions from A (1), we reach Z (26) then Y (25), so effectively -2. From 25 to 23: -2 again. So the first letters follow a constant step of -2. Next: 23 - 2 = 21, which is U. Step 3: Second letters sequence: A, W, S, O. Positions: 1, 23, 19, 15. From 1 to 23: stepping back 4 positions from A yields W, so -4. From 23 to 19: -4. From 19 to 15: -4. Next: 15 - 4 = 11, which is K. Step 4: Third letters sequence: L, F, Z, T. Positions: 12, 6, 26, 20. From 12 to 6: -6. From 6 to 26: again -6 with wrap around. From 26 to 20: -6. Next: 20 - 6 = 14, which is N. Step 5: Combine the predicted letters. First U, second K, third N, giving UKN.

Verification / Alternative check:
We can view all three sequences clearly: First letters: 3, 1, 25, 23, 21 (all -2 mod 26). Second letters: 1, 23, 19, 15, 11 (all -4). Third letters: 12, 6, 26, 20, 14 (all -6). The use of constant backward steps with wrap around is a classic exam pattern. Only UKN uses the correct letters at each position to respect all three independent subtraction rules. Hence, UKN is the unique term that extends the series consistently.

Why Other Options Are Wrong:
A) UJO matches the first letter but fails for the second and third letters, which do not follow the -4 and -6 progressions. B) VKP starts with V instead of U, breaking the -2 rule for first letters. D) VJP similarly misaligns all three positions with the established numeric patterns.

Common Pitfalls:
Candidates sometimes overlook the idea of constant negative steps and instead look for more complicated relationships. Others may become confused by wrap around movement from A to Z and think the pattern is irregular. The safe method is to note that subtraction can be applied modulo 26, so a move from 1 to 25 is a simple -2, and from 6 to 26 can be -6 with wrapping. Embracing this circular interpretation makes backward alphabet sequences much easier to handle.

Final Answer:
The triplet that correctly completes the series CAL, AWF, YSZ, WOT, ? is UKN.