Under what circumstances are composite primary keys appropriate?

A composite primary key is a set of several primary keys that, together, uniquely identifies each record.
Primary keys are used as identifiers of composite entities. In this case each primary key combination is allowed only once in the *:* relationship.
Other case where primary keys are used is as identifiers of weak entities, where the weak entity has a strong identifying relationship with the parent entity. 

The correct answer is "denied"

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