Which statement best describes semi-structured data?

• A. It is completely unstructured with no metadata.
• B. It is fully structured with a rigid schema.
• C. It is defined by a metadata registry that is always identical across datasets.
• D. It has tags or markers like JSON or XML.

Answer: (D)

Semi-structured data combines flexible organization with embedded meaning through tags or markers. It uses self-describing formats where the data itself carries structure, such as JSON or XML, so each item can include its own keys, elements, or attributes without requiring a single rigid schema for all records. This allows variability in fields while still providing enough markers to interpret the data.

Completely unstructured data lacks reliable metadata to guide interpretation, so it doesn’t rely on embedded structure. Fully structured data uses a fixed schema and rigid fields, which is the opposite of semi-structured. A metadata registry that is identical across datasets implies uniform external metadata, not the self-describing, flexible structure characteristic of semi-structured data.