Meaningless Roman Numeral

Definition
A Roman numeral is a numerical system used in ancient Rome that uses letters to represent values. The letters are combined to represent numbers. However, not all combinations of letters are valid in the Roman numeral system.

Explanation
In the given options, the Roman numeral 'IXIV' is meaningless. This is because it violates the rules of the Roman numeral system. In Roman numerals, there are only seven letters that are used to represent numbers. These letters are I, V, X, L, C, D, and M. The rules for writing Roman numerals are as follows:

- The letters I, X, and C can only be repeated up to three times in a row.
- The letters V, L, and D cannot be repeated.
- The letter I can be placed before V and X to make numbers such as IV and IX.
- The letter X can be placed before L and C to make numbers such as XL and XC.
- The letter C can be placed before D and M to make numbers such as CD and CM.

Analysis
When we analyze the given options, we can see that all the other options follow the rules of the Roman numeral system. Option a) XV represents the number 15, option b) XIX represents the number 19, and option d) XXIV represents the number 24. However, option c) IXIV violates the rules of the Roman numeral system because the letter I is repeated four times in a row, which is not allowed.

Conclusion
In conclusion, the Roman numeral that is meaningless in the given options is option c) IXIV. This is because it violates the rules of the Roman numeral system by repeating the letter I four times in a row.