What type of definition fails to identify differences between categories?

The correct choice identifies a type of definition that does not effectively clarify or differentiate between categories or concepts. A "distinction without a difference" refers to a situation where a distinction is claimed, but it does not lead to any meaningful separation of categories. Instead, it often results in confusion or an unclear understanding because the supposed differences do not actually hold significant weight or relevance.

For instance, if two categories are described with minor or trivial distinctions that do not affect their core characteristics or functionalities, the definition fails to provide valuable information. This can make it challenging for individuals to understand the unique attributes of each category, as the lack of meaningful differentiation leads to ambiguity.

In contrast, other definitions like descriptive, comparative, or clarified aim to provide clarity. A descriptive definition outlines essential characteristics, a comparative definition evaluates similarities and differences, and a clarified definition seeks to eliminate confusion by providing precise meanings. Each of these definitions plays a role in establishing clear distinctions, making them effective tools in communication and understanding.