In this letter pair pattern question, identify the pair that does not follow the same alphabetical distance rule as the others: PD, LE, IC and DB.

Introduction / Context:
This odd one out question uses two letter pairs and expects you to spot a structural difference between them. There are several possible properties to check: distance between letters, order or whether the letters are vowels and consonants. Here, a simple and clear difference arises from the type of letters used in each pair, which is a common pattern in verbal reasoning.

Given Data / Assumptions:

• The letter pairs are PD, LE, IC and DB.
• We take vowels as A, E, I, O, U and other letters as consonants.
• We examine the composition of each pair in terms of consonant consonant or consonant vowel.

Concept / Approach:
The initial observation is that three of the pairs consist entirely of consonants, while one pair has a consonant followed by a vowel. Once we confirm this, we can clearly identify which pair is structurally different. Instead of focusing only on numerical positions, this question relies on vowel consonant classification.

Step-by-Step Solution:
Step 1: For PD, P is a consonant and D is also a consonant, so PD is a consonant consonant pair. Step 2: For IC, I is a vowel while C is a consonant, making IC a vowel consonant pair. Step 3: For DB, D and B are both consonants, so DB is another consonant consonant pair. Step 4: For LE, L is a consonant and E is a vowel, making LE a consonant vowel pair. Step 5: Among the four options, PD and DB are consonant consonant, IC is vowel consonant, and LE is consonant vowel. The most natural grouping is that PD, IC and DB all end with consonants, whereas LE ends with a vowel. So LE can be taken as the odd one out due to ending in a vowel while others end in consonants.

Verification / Alternative check:
Another way to see the distinction is to look only at the second letters of each pair. D in PD is a consonant, E in LE is a vowel, C in IC is a consonant and B in DB is a consonant. Thus three pairs (PD, IC and DB) have a consonant in the second position, while LE has a vowel. Therefore LE alone breaks the common pattern of having a consonant as the second letter, which confirms that LE is the odd one out.

Why Other Options Are Wrong:
PD is wrong as the odd one out because it ends with a consonant, matching the pattern seen in IC and DB. IC is wrong as the odd one out because its second letter C is a consonant, again consistent with PD and DB. DB is wrong as the odd one out because it is another pair whose second letter is a consonant.

Common Pitfalls:
Students may initially attempt to use alphabet positions and number differences between letters, which can be confusing here. Another mistake is to focus only on whether the first letter is consonant or vowel, which does not create a clear majority. Concentrating on the second letter and noting that three second letters are consonants while one is a vowel reveals the intended pattern quickly.

Final Answer:
The only pair whose second letter is a vowel rather than a consonant, and hence the odd one out, is LE.