What is the main purpose of a data dictionary?

The main purpose of a data dictionary is to define and describe data set elements. A data dictionary provides detailed information about the data contained in a database or a dataset, including the names of fields, types of data they contain, constraints, and relationships between different data elements. This structured documentation is essential for data governance, ensuring that everyone using the data understands what each element represents, its format, and how it can be used.

Having a well-defined data dictionary promotes consistency in data usage, assists in data management, and improves communication among team members who work with the data. It's particularly useful for data analysts, developers, and anyone involved in data-related projects, as it serves as a comprehensive reference guide.

The other options focus on aspects such as data security, statistical calculations, and data visualization, which, while important in their own right, do not embody the primary function of a data dictionary. The emphasis here remains on defining and describing data elements, making option B the most appropriate choice.