Final answer:
Poly-structured data refers to a mix of different data types including structured, semi-structured, and unstructured data. SQL and XML databases contain structured data while videos and audios are examples of unstructured data. Thus, all these data types belong to poly-structured data.
Step-by-step explanation:
The poly-structured data refers to data that includes a mix of structured and unstructured data types. In the context of the given question:
- Data in SQL databases (Option A) are usually referred to as structured data because they reside in fixed fields within a record or file and are organized in tables with rows and columns.
- Data in XML databases (Option B) can also be considered structured because they are well-defined and can be easily parsed, despite their hierarchical structure.
- Unstructured data like videos and audios (Option C) does not follow a predefined data model, thus are not easily searchable without the use of special algorithms or tagging.
Therefore, the correct answer would be D.All of the above, since poly-structured data encompasses a variety of data formats including structured, semi-structured, and unstructured data.