Explanation:

To find the odd number/letters/word from the given alternatives, we need to carefully analyze each option and identify the pattern or rule that applies to the numbers/letters/words in the options. Let's analyze each option one by one:

a) 547 - 563:
- The numbers in this option are 547 and 563.
- There doesn't seem to be any obvious pattern or rule between these numbers.
- Both numbers are odd and have three digits.
- Therefore, this option does not have an odd number/letter/word.

b) 71 - 55:
- The numbers in this option are 71 and 55.
- One possible pattern that can be observed is that the second number (55) is obtained by reversing the digits of the first number (71).
- However, both numbers are odd and have two digits.
- Therefore, this option does not have an odd number/letter/word.

c) 517 - 523:
- The numbers in this option are 517 and 523.
- There doesn't seem to be any obvious pattern or rule between these numbers.
- Both numbers are odd and have three digits.
- Therefore, this option does not have an odd number/letter/word.

d) 248 - 231:
- The numbers in this option are 248 and 231.
- One possible pattern that can be observed is that the second number (231) is obtained by subtracting 17 from the first number (248).
- Both numbers are even and have three digits.
- Therefore, this option has an odd number/letter/word.

Conclusion:

After analyzing each option, we can conclude that the odd number/letter/word is present in option 'd' (248 - 231).