A series of three-letter groups is given with one term missing. Select the correct group that will complete the sequence: PNR, RQV, TTZ, ?, XZH.

Introduction / Context:
This is an alphabetical series question where each term is a three-letter group. You are given PNR, RQV, TTZ, ?, XZH and need to determine which option best fills the gap so that the pattern in each letter position is preserved across the entire sequence.

Given Data / Assumptions:

• Series: PNR, RQV, TTZ, ?, XZH.
• Each term has three letters.
• The pattern is assumed consistent across all positions.
• Alphabet positions: A = 1, B = 2, ..., Z = 26, with wrap-around where needed.

Concept / Approach:
We treat the first, second and third letters as three separate sequences. For each position, we convert letters to their numeric positions and look for a regular pattern of increments, taking into account alphabet wrap-around. Once the numeric pattern is clear, we extend it by one term and convert the results back into letters to obtain the missing group.

Step-by-Step Solution:
Step 1: First letters: P, R, T, ?, X. Positions: P = 16, R = 18, T = 20, X = 24. From 16 to 18: +2; from 18 to 20: +2. Continuing the +2 pattern, after T (20) we expect 22, which is V. So the missing first letter is V. Step 2: Second letters: N, Q, T, ?, Z. Positions: N = 14, Q = 17, T = 20, Z = 26. From 14 to 17: +3; from 17 to 20: +3. Following this, after T (20) we expect 23, which is W. So the missing second letter is W. Step 3: Third letters: R, V, Z, ?, H. Positions: R = 18, V = 22, Z = 26, H = 8. From 18 to 22: +4; from 22 to 26: +4; from 26 we add 4 and wrap around: 26 + 4 = 30, 30 - 26 = 4, which is D. Then from 4 to 8 is another +4. So the pattern is +4 with wrap-around. Step 4: Therefore the missing third letter, between Z (26) and H (8), must be D (4). Step 5: Combine the results from all three positions: V as the first letter, W as the second letter, and D as the third letter. The missing term is VWD.

Verification / Alternative check:
Write all terms numerically: PNR (16,14,18), RQV (18,17,22), TTZ (20,20,26), VWD (22,23,4), XZH (24,26,8). First column: 16,18,20,22,24 (all +2). Second column: 14,17,20,23,26 (all +3). Third column: 18,22,26,4,8 (all +4 with wrap-around after 26). VWD is therefore the only term that fits all three patterns perfectly.

Why Other Options Are Wrong:
Option A (VWB): The third letter B is position 2, which does not fit the +4 pattern between Z (26) and H (8), where the intermediate term must be D (4). Option B (UXC): The first letter U is 21, which disrupts the +2 pattern, and the second letter X is 24, not the correct +3 step from T (20). Option D (UXE): Both the first and second letters fail the +2 and +3 patterns, and the third letter E is 5, not part of the correct +4 sequence that requires D (4).

Common Pitfalls:
Candidates sometimes focus on only one column, notice a partial match, and choose that option prematurely. Another frequent issue is ignoring alphabet wrap-around when letters go beyond Z. Always test each position thoroughly and remember that after Z (26), the sequence can wrap around to A (1) while still maintaining a fixed numeric increment.

Final Answer:
The group of letters that correctly completes the series is VWD, which corresponds to option C.