A sequence of three letter groups is given with the first term missing. Identify the group that fits before ONM, GFE, XWV: ?, ONM, GFE, XWV.

Introduction / Context:
This question presents three letter groups in descending order and asks you to find a missing starting group. Each given group, such as ONM, GFE, and XWV, consists of three consecutive letters written backwards. Your task is to find a similar descending triplet that best fits as the first element of the sequence.

Given Data / Assumptions:

• Known part of the sequence: ONM, GFE, XWV. • Each given group is a descending sequence of three consecutive letters. • Standard alphabet positions A = 1 to Z = 26 are assumed. • The missing term should logically match this style of three letter descending clusters.

Concept / Approach:
We first note the internal structure of each known group: ONM is O, N, M descending; GFE is G, F, E descending; XWV is X, W, V descending. These are all three step backward sequences. Because the question only asks which term fits as the missing first group, and all answer options are also three letter groups, we must choose the one that is also a descending consecutive triplet and fits naturally with the others.

Step-by-Step Solution:
Step 1: Describe the structure of the existing groups. ONM = O (15), N (14), M (13) descending by 1. GFE = G (7), F (6), E (5) descending by 1. XWV = X (24), W (23), V (22) descending by 1. Step 2: Examine the options. TUV is ascending: T (20), U (21), V (22). VUT is descending: V (22), U (21), T (20). GHI and PQR are ascending sequences. Step 3: Since the known triplets are all descending by one step, the missing group must also be a descending triplet. Only VUT matches this structure.

Verification / Alternative check:
We can view the four triplets as independent examples of the same pattern: each is a block of three consecutive letters in reverse order. VUT belongs to the same category as ONM, GFE, and XWV. The other options do not fit because they move forward instead of backward. The problem does not impose a strict numeric pattern on starting letters, it mainly insists on structural similarity of each block.

Why Other Options Are Wrong:
• TUV: This is an ascending sequence and does not match the descending style of ONM, GFE, or XWV. • GHI: Also ascending, and moreover it would duplicate the letter G from GFE in a way that does not enhance any broader pattern. • PQR: Another ascending sequence that has no clear structural link to the three descending groups already present.

Common Pitfalls:
Many candidates try to impose a strict arithmetic rule that connects the starting letters numerically, even when the main intention is only structural similarity within each block. This can lead to overcomplication. When multiple choices are available, always check for simple shared features first, such as ascending or descending order, before searching for deeper numeric relationships.

Final Answer:
The group that best fits before ONM, GFE, and XWV is VUT.