In the following question, each option shows a group of three lowercase letters. In three groups, the pattern of letters is vowel–consonant–vowel, while in one group the last letter is a consonant. Select the group which does not follow the vowel–consonant–vowel pattern (odd group out).

Introduction / Context:
This question belongs to the verbal reasoning category and deals with simple letter patterns. Instead of focusing on alphabetical positions, it uses the classification of letters into vowels and consonants. You are asked to identify which three letter group does not follow the same vowel–consonant–vowel structure as the others. Such pattern recognition is common in odd one out and series questions in aptitude exams.

Given Data / Assumptions:
- The options are eno, iqa, ubu, olr, and afa.
- The English vowels are a, e, i, o, u, and all other English letters are consonants.
- In most groups, the first and third letters are vowels, while the middle letter is a consonant, giving a vowel–consonant–vowel structure.
- Exactly one group does not follow this vowel–consonant–vowel pattern and is the odd one out.

Concept / Approach:
The straightforward method is to classify each letter in every group as a vowel or a consonant and then note the pattern. A group that follows vowel–consonant–vowel will look like V–C–V. The group that breaks this structure will show a different pattern such as vowel–consonant–consonant. Once the patterns are written out clearly, it becomes easy to identify which group is different from the others.

Step-by-Step Solution:
Step 1: For eno, letters are e, n, o. Here e is a vowel, n is a consonant, and o is a vowel. Pattern is V–C–V.Step 2: For iqa, letters are i, q, a. Here i is a vowel, q is a consonant, and a is a vowel. Pattern is V–C–V.Step 3: For ubu, letters are u, b, u. Here u is a vowel, b is a consonant, and u is a vowel. Pattern is again V–C–V.Step 4: For afa, letters are a, f, a. Here a is a vowel, f is a consonant, and a is a vowel. Pattern is V–C–V.Step 5: For olr, letters are o, l, r. Here o is a vowel, but both l and r are consonants. Pattern is V–C–C, not V–C–V.Step 6: Therefore, olr is the only group that does not end with a vowel and breaks the vowel–consonant–vowel pattern, making it the odd one out.

Verification / Alternative check:
Another way to check is to focus first on the last letter of each group. In eno, iqa, ubu, and afa, the last letter is a vowel. In olr, the last letter r is a consonant. Since the first four groups share the pattern vowel at the beginning and vowel at the end, while olr does not, this confirms that olr stands apart from the rest.

Why Other Options Are Wrong:
eno, iqa, ubu, and afa each have the first and last letters as vowels and the middle letter as a consonant. This consistent V–C–V pattern joins them together as one family of letter groups. Because they follow the same structure, none of these four can be considered the odd one out in this question.

Common Pitfalls:
Students sometimes rush and misclassify letters, especially if they are not comfortable with vowels and consonants. Another mistake is to look for complex alphabetic differences when a simple vowel consonant classification is enough. To improve accuracy, always take a second to mark V or C under each letter when dealing with such pattern questions. This small step reduces confusion and quickly reveals the odd element.

Final Answer:
olr