Which of the following best describes nominal level measures?

Nominal level measures are used to categorize data without any quantitative value or order. This means that they consist of categories that are mutually exclusive and collectively exhaustive, allowing researchers to label different groups. For example, categories such as gender, race, and type of crime fall under nominal measures. Importantly, while you can count the frequency of occurrences in each category, you cannot perform any mathematical operations on these values; they are purely qualitative in nature.

Options suggesting that nominal measures have a meaningful zero point or involve ranking or ordered categories misrepresent their fundamental characteristics. Nominal data is not concerned with quantities or ordering, emphasizing that different categories may not have any hierarchy or numerical significance. Thus, the essence of nominal measures lies in their identification and classification of variables, devoid of any mathematical interpretation, which is precisely what makes option C the best choice.