A flat file is a database in which information:

A flat file database is characterized by its simple structure, where all information is stored in a single table or file. This means that the data is presented in a two-dimensional format, consisting of rows and columns, with each row representing a record and each column representing a field of data. This structure makes flat file databases easy to manage and understand, as there are no complex relationships or dependencies across multiple tables. The simplicity of a flat file database is particularly beneficial for smaller applications or where data relationships do not need to be complex, allowing for straightforward access and manipulation of data.

In contrast, the other options, which involve multiple tables or hierarchical organization, pertain to more complex database structures, such as relational databases or hierarchical databases, that manage relationships between different datasets, leading to a level of complexity not found in flat file databases.