Which of the following is an example of structured data?

Structured data refers to information that is highly organized and easily searchable, often formatted in a predictable manner. This type of data is typically stored in relational databases and can be easily analyzed because it adheres to a specific schema or structure. An example of structured data includes attributes like customer name, date of birth (DOB), email address, and date of transaction. Each of these pieces of information can be categorized, sorted, and queried within a database due to their defined formats, such as string and date types.

In contrast, the other options represent unstructured or semi-structured data. Comments on a webpage and text messages contain free-form text and lack a predefined format that makes them easily analyzable. Videos of a presentation are multimedia content that also do not follow a structured format. Each of these forms involves complex data that requires more advanced techniques, such as text analysis or image recognition, to extract meaningful insights. Thus, the choice highlighting customer-related information clearly exemplifies structured data.