Finding the odd one out- 41, 43, 47, 53, 61, 71, 73, 81

Odd one out means finding the number that does not follow the pattern of the other numbers in the given series. Let's analyze the given series of numbers:

- All the given numbers are prime numbers except 81.
- All the prime numbers in the given series are odd except 2 numbers- 53 and 81.
- All the prime numbers except 2 numbers- 2 and 3, are ending with either 1, 3, 7 or 9.

Now, let's apply these observations to find the odd one out:

- 41- Prime number, odd and ending with 1. It follows the pattern.
- 43- Prime number, odd and ending with 3. It follows the pattern.
- 47- Prime number, odd and ending with 7. It follows the pattern.
- 53- Prime number, but it's an even number (not odd), so it does not follow the pattern. It is the odd one out.
- 61- Prime number, odd and ending with 1. It follows the pattern.
- 71- Prime number, odd and ending with 1. It follows the pattern.
- 73- Prime number, odd and ending with 3. It follows the pattern.
- 81- Not a prime number, even number (not odd) and ending with 1. It does not follow the pattern, but it is not the odd one out because we are looking for a prime number that does not follow the pattern.

Therefore, the odd one out in the given series is 53.

Answer ( D ) 81