Final answer:
A single table independent of other files is referred to as an Entity. It represents a real-world object or concept that data can be stored about in relational databases.
Step-by-step explanation:
When independent of any other files related to it, a single table is referred to as a: b) Entity.
In the context of databases, an entity can be anything about which data can be stored. A single table that holds data is a representation of such an entity. In relational database terminology, a table often corresponds to an entity type, where each row (also called a record) represents an instance of that entity type and each column represents an attribute of the entity.
A standalone table by itself is not sufficient to be considered a full-fledged database, as a database usually comprises multiple related tables, queries, reports, and other objects. An instance typically refers to a specific situation or occurrence of an object, and thus, doesn't fit this context. Given this information, the correct answer is 'Entity' which reflects the table's role in representing a real-world object or concept.