Identify the key, which is a column (or attribute) or a group of columns in a table in RDBMS that is used to uniquely identify the rows of data in that table.

Correct option is B

In a Relational Database Management System (RDBMS), the Primary key is used to uniquely identify each row in a table. The primary key ensures that no two rows have the same value for the primary key column(s). It must contain unique values and cannot have NULL values.
Key Definitions:
1. Primary key: A column (or a group of columns) in a table that uniquely identifies each row in the table. It cannot have duplicate or NULL values.
2. Candidate key: A set of columns that can uniquely identify rows in a table. A table can have multiple candidate keys, but only one can be chosen as the primary key.
3. Alternate key: A candidate key that is not selected as the primary key. It can still uniquely identify rows in the table.
4. Foreign key: A column (or a group of columns) in a table that is used to establish a link between the data in two tables. It refers to the primary key of another table.
Important Key Points:
1. Primary key uniquely identifies each record in a table.
2. A primary key can consist of one or more columns (attributes).
3. Foreign key is used to establish relationships between tables, not for uniquely identifying rows in a single table.
Knowledge Booster:
· Option (a): Candidate key is a set of columns that can uniquely identify rows, but it's not necessarily the one chosen to be the primary key.
· Option (c): Alternate key refers to a candidate key that wasn't chosen as the primary key. It's still capable of uniquely identifying rows, but it’s not the primary key.
· Option (d): Foreign key is used to create relationships between tables, but it doesn’t uniquely identify rows within a single table.