Which of the following best describes a flat file?

A flat file is best described as a file with data organized in a single sheet format. This means that all the data is stored in a tabular form, typically within rows and columns, similar to a spreadsheet. Flat files can contain multiple records and fields but do not support complex structures such as hierarchical or relational data organization.

This single-dimensional structure is what differentiates a flat file from more complex data formats like databases, which can handle relationships between different entities or data structures. Flat files are often used for simple data storage and manipulation tasks due to their straightforward format, making them easy to read and edit.

The other options present characteristics that do not align with the concept of a flat file. Hierarchical data structures, which involve parent-child relationships, pertain more to databases that support such dimensions. Automated updates with live data suggest functionality typical of dynamic databases rather than static flat files. Finally, while text entries can be part of a flat file, this definition is too narrow as flat files can also store numeric, date, and various other data types. In essence, the defining feature of flat files lies in their single-sheet organization of data.