The primary key constraint enforces uniqueness. Attempting to insert a duplicate value will result in an error, and the operation will be aborted to maintain entity integrity.

TCL stands for Transaction Control Language. Its commands are used to manage transactions in the database. ROLLBACK is a TCL command that undoes transactions or changes that have not yet been saved to the database.

The `CREATE TABLE` command is a Data Definition Language (DDL) statement used to define a new table and specify its columns and their data types.

A primary key must be a unique identifier for each record in a table. Fields like Class, GPA, or Major can have duplicate values for different students. A Social Security Number, however, is unique to each individual and therefore serves as an excellent primary key.

With only one non-key attribute, there can be no transitive dependency (a non-key depending on another non-key). If the table has a single-attribute primary key, it is also in 2NF. Therefore, it is guaranteed to be in at least 3NF.

SQL (Structured Query Language) is a powerful language designed for managing and manipulating relational databases. It is functionally divided into several sub-languages, each serving a distinct purpose: * **Data Definition Language (DDL):** This includes commands used to define, alter, and drop database structures. Examples include `CREATE TABLE`, `ALTER TABLE`, and `DROP DATABASE`. * **Data Manipulation Language (DML):** This set of commands is used for managing data within schema objects. Common DML commands are `SELECT` (to retrieve data), `INSERT` (to add new data), `UPDATE` (to modify existing data), and `DELETE` (to remove data). * **Data Control Language (DCL):** These commands are used to control access to data and the database. Examples include `GRANT` (to give user privileges) and `REVOKE` (to remove user privileges). While Transaction Control Language (TCL) (e.g., `COMMIT`, `ROLLBACK`) is also an important part of SQL, DDL, DML, and DCL represent the fundamental and most commonly recognized categories of SQL's capabilities. Option A correctly lists these three core components.

The Database Administrator, or DBA, is the professional responsible for managing and maintaining the database environment, including security, performance, backups, and recovery.

In the context of a database, a form primarily serves as a user interface for data entry and viewing. Its definition controls the layout and placement of data fields on the screen to create an intuitive user experience.

DDL commands are used to define and manage the database schema. `CREATE` builds objects, `ALTER` modifies them, and `DROP` deletes them.

In a modern database architecture, the DBMS itself is responsible for low-level tasks like data storage and access control. Application programs are built on top of the DBMS to perform the specific business logic and processing functions required by the user.