Database applications typically support which classes of operations on stored data? Select the most complete statement.

Introduction / Context:
Database applications implement CRUD operations: Create, Read, Update, and Delete. These operations are fundamental to managing persistent data for business processes, analytics, and applications of all sizes.

Given Data / Assumptions:

• The question lists adding, reading, and updating, which correspond to three of the CRUD actions.
• Typical RDBMS and application frameworks support all CRUD operations with permissions and constraints.

Concept / Approach:
SQL statements such as INSERT (create), SELECT (read), UPDATE (update), and DELETE (delete) embody CRUD in relational systems. Applications expose these through forms, APIs, and services. Security and validation govern who can perform which operations.

Step-by-Step Solution:

Verification / Alternative check:
Any standard application (for example, inventory, CRM) requires creating new entries, reading them, and modifying them as statuses or attributes change.

Why Other Options Are Wrong:

• Single operations (a, b, c) are incomplete—practical apps need all.
• Read-only databases exist in special contexts, but typical applications are not read-only.

Common Pitfalls:
Confusing data access permissions with system capability. Even if a user is read-only, the system as a whole still supports full CRUD via authorized roles.

Final Answer:
All of the above.