In each of the following three letter groups, the letters follow a certain positional pattern in the English alphabet. Select the group of letters that is the odd one out because it does not follow the same pattern as the other three.

Introduction / Context:
This reasoning question is based on alphabetical patterns in three letter groups. Three of the options follow the same pattern when you look carefully at the positions of the letters in the English alphabet, while one option breaks that pattern. Your task is to identify the group of letters that is the odd one out. Such questions are common in competitive exams to test attention to detail, pattern recognition, and basic familiarity with the alphabetical order.

Given Data / Assumptions:
- We use the standard English alphabet from A to Z with positions A = 1, B = 2, C = 3 and so on up to Z = 26.
- The four options are three letter groups: FHG, NOP, TVU, and WYX.
- We assume that the pattern, if any, is created by moving forward or backward by a fixed number of positions in the alphabet.
- The odd group will be the one that does not follow the same movement pattern as the others.

Concept / Approach:
The key idea is to convert each letter into its numerical position in the alphabet and then analyze how the second and third letters are obtained from the first letter. If most options follow one type of movement, such as plus two then minus one, and only one option has a different movement, that option is the odd one out.

Step-by-Step Solution:
Step 1: For FHG, positions are F = 6, H = 8, G = 7. From 6 to 8 we move +2, and from 8 to 7 we move -1.Step 2: For NOP, positions are N = 14, O = 15, P = 16. From 14 to 15 we move +1, and from 15 to 16 we again move +1.Step 3: For TVU, positions are T = 20, V = 22, U = 21. From 20 to 22 we move +2, and from 22 to 21 we move -1.Step 4: For WYX, positions are W = 23, Y = 25, X = 24. From 23 to 25 we move +2, and from 25 to 24 we move -1.Step 5: Compare the movement patterns. Three options follow +2 then -1, while one option follows +1 then +1.

Verification / Alternative check:
We can verify our conclusion by rewriting the movements in a compact form. FHG, TVU, and WYX all follow the pattern first letter +2 gives second letter, and second letter -1 gives third letter. NOP progresses as first letter +1 gives second letter, and second letter +1 gives third letter. Since this is clearly different, NOP is the odd group.

Why Other Options Are Wrong:
FHG is not odd because it fits the +2 then -1 pattern. TVU also fits the same +2 then -1 pattern. WYX again follows the same +2 then -1 movement. Since these three share a common rule, they cannot be considered the odd ones out. Only NOP violates that rule.

Common Pitfalls:
Many learners quickly focus on whether the letters are in alphabetical order or reversed, instead of looking at the exact numerical differences. Another common mistake is to consider that NOP looks simple and regular, so it must be correct, when in fact the correct approach is to find the majority pattern and then highlight the one that does not follow that majority. Forgetting to convert letters into positions can also make the pattern hard to see.

Final Answer:
The odd group of letters is NOP, because it follows a +1, +1 pattern, while all the other groups follow a +2, -1 pattern.