In this alphabet pattern reasoning question, select the odd group of letters from the following alternatives: USQ, OMK, IGE and VUT.

Introduction / Context:
This question involves recognizing patterns in sequences of letters. The given groups are USQ, OMK, IGE and VUT. In three of these groups, the letters move backward in the alphabet in equal steps of two positions. One group instead moves backward in steps of one position. Identifying the difference in step size is the key to finding the odd group of letters.

Given Data / Assumptions:

• Letter groups: USQ, OMK, IGE and VUT.
• Alphabet positions: A = 1, B = 2, ..., Z = 26.
• We focus on whether the letters form a descending sequence and whether the step size is constant.
• Exactly one group has a different step size pattern from the others.

Concept / Approach:
We convert each letter to its position in the alphabet and calculate the differences from the first letter to the second, and from the second to the third. If three groups show a descending pattern with a constant step of minus two positions, and one group shows a different set of steps, that one is the odd group out. This pattern based method is standard for alphabet series questions.

Step-by-Step Solution:
Step 1: Analyze USQ.U = 21, S = 19, Q = 17. Differences are 21 to 19 = -2 and 19 to 17 = -2. So USQ descends by two positions each time.Step 2: Analyze OMK.O = 15, M = 13, K = 11. Differences are 15 to 13 = -2 and 13 to 11 = -2. OMK also descends in steps of two.Step 3: Analyze IGE.I = 9, G = 7, E = 5. Differences are 9 to 7 = -2 and 7 to 5 = -2. IGE again follows the same -2, -2 pattern.Step 4: Analyze VUT.V = 22, U = 21, T = 20. Differences are 22 to 21 = -1 and 21 to 20 = -1. In this group, the letters descend by one position each time, not by two.Step 5: Identify the odd group.USQ, OMK and IGE all show a regular backward jump of two letters, while VUT shows jumps of one letter. Therefore VUT is the odd group out.

Verification / Alternative check:
You can also verify this visually by writing the alphabet and tracing the jumps. For USQ you jump from U to S to Q skipping one letter each time. For OMK and IGE you follow the same skip of one letter between steps. For VUT, however, you move from V to U to T without skipping any letters, which is a closer spacing. This confirms that VUT does not share the same skip pattern seen in the other three sequences.

Why Other Options Are Wrong:
USQ: Follows a descending sequence with constant step size -2, so it fits the main pattern.
OMK: Also descends by two positions in each step, consistent with USQ and IGE.
IGE: Another descending sequence with step -2, matching the majority pattern.

Common Pitfalls:
Candidates sometimes only check whether the letters are descending or ascending and ignore the exact step size. In this question, all four groups are descending, so you need to go one step further and compare how many positions each step covers. Always examine both direction and step size when you get letter sequences with more than one possible rule.

Final Answer:
The odd group of letters is VUT, because it descends by one step at a time, while the other three groups descend by two steps at a time in the alphabet.