In the following question, select the odd number arrangement from the alternatives given below. Three options contain the same set of digits (2, 3, 4) arranged differently, while one option contains a different digit set. Identify the odd one out. (A) 234 (B) 345 (C) 243 (D) 432 (E) 324

Introduction / Context:
This odd-one-out problem is based on digit composition. Many number arrangement questions hide a simple rule: several options are permutations of the same digits, while one option includes an extra or different digit. The odd option is the one with a different digit set.

Given Data / Assumptions:

• We compare the digits used in each 3-digit number.
• Permutations mean the same digits are present but in different order.
• The odd one out uses at least one different digit.

Concept / Approach:
List the digits of each option and see whether most options share the same digit set. If four options use digits 2,3,4 and one uses a different set, the different one is the odd choice.

Step-by-Step Solution:

Verification / Alternative check:
A quick verification is to look for digit '5'. Only 345 contains a 5. All other numbers are built only from digits 2, 3, and 4. Therefore 345 cannot be a permutation of the others and is the odd one out.

Why Other Options Are Wrong:

Common Pitfalls:
Students sometimes focus on increasing/decreasing order and miss that the digits themselves are the key. Another mistake is thinking 345 is odd only because it is increasing, but 234 is also increasing. The correct reasoning is about digit set consistency, not ordering alone. Always check whether the same digits repeat across multiple options.

Final Answer:
345