Which of the following best defines a knowledge graph?

A knowledge graph is fundamentally a structured representation of knowledge and relationships. This means that it organizes information about entities (such as people, places, and concepts) and the connections between them in a way that machines can understand. Knowledge graphs use nodes to represent entities and edges to indicate relationships, facilitating better data organization, search, and retrieval. This structured format makes it possible to extract meaningful insights and facilitate more effective reasoning about relationships among diverse types of information.

In contrast to the options that imply other forms of data representation or machine learning, the emphasis of a knowledge graph is on the explicit relationships and structured format that define how knowledge is interconnected. Thus, option C is the most accurate and comprehensive definition of a knowledge graph.