Explanation:

To find the odd numeral group, we need to look for a pattern or rule that applies to all the given numerals. By doing so, we can identify the numeral that does not follow the pattern and is therefore the odd one out. Let's examine each numeral group:

a) 361:
- The first digit is the square of the last digit (6 x 6 = 36).
- The middle digit is the sum of the first and last digits (3 + 1 = 4).
- This group follows the pattern.

b) 381:
- The first digit is one more than the second digit (3 - 1 = 2).
- The last digit is one more than the second digit (8 - 1 = 7).
- This group does not follow the pattern.

c) 324:
- The first digit is the square of the last digit (4 x 4 = 16).
- The middle digit is the difference between the first and last digits (3 - 2 = 1).
- This group follows the pattern.

d) 484:
- The first and last digits are the same.
- The middle digit is the square of the first and last digits (4 x 4 = 16).
- This group follows the pattern.

Conclusion:

Out of the given numeral groups, the odd one out is (b) 381, as it does not follow the pattern observed in the other numeral groups.