Correct Answer:
C. c) Super key
A super key is actually a set of one or more attributes that uniquely identify a record.
Breakdown of the options:
Super key: Any set of attributes that uniquely identifies a tuple (row) in a relation (table).
Candidate key: A minimal super key (no unnecessary attributes).
Primary key: A chosen candidate key to uniquely identify a record.
Foreign key: A field in one table that refers to the primary key in another table.
So, while a super key is a broader term encompassing any set of attributes that uniquely identify a record, it's not the most specific or commonly used term. Candidate key or primary key would be more appropriate in most cases.