"student ID, number and title" is the correct answer for the above question.
Explanation:
The primary key is used to read the data of a table. It can not be duplicated or null for any records.
The "student ID" is used to identify the data of the "student" entity. It is because the "student ID" can not be duplicated or null for any records. It is because every student has a unique "student ID".
The "number" is used to identify the data of the "Locker" entity. It is because the "number" can not be null or duplicate for any records. It is because every locker has a unique "number".
The "title" is used to identify the data of the "Movie" entity. It is because the "title" can not be Null or duplicate for any records. It is because every movie has a unique "title".