Which of the following best describes unstructured data?

Unstructured data is characterized by the absence of a predefined format or structure, making it difficult to organize and analyze using traditional data processing methods. This type of data does not fit neatly into tables or schemas, and it often includes formats such as text documents, images, videos, emails, social media posts, and more. Because unstructured data lacks a specific structure, it requires advanced techniques such as natural language processing and machine learning to extract valuable insights from it.

The other options describe characteristics that are typically associated with structured data. Structured data, for example, is organized in a defined format, such as tables with rows and columns, making it easily searchable and manageable. Numerical data represents a specific type of structured data, while data stored in relational databases is inherently structured due to its organizational schema, which helps facilitate easy access and query capabilities. Therefore, the correct answer effectively captures the defining feature of unstructured data, distinguishing it from structured formats.