Three-Tier Architecture — Layer Composition What does a classic three-tier application architecture include?

Introduction:
Three-tier architectures separate concerns into presentation (client), application (business logic), and data (persistence). This structure improves scalability, maintainability, and team specialization. The question checks whether you can identify the correct tier composition.

Given Data / Assumptions:

• Presentation focuses on UI and interaction.
• Application (middle) tier hosts business rules and orchestration.
• Data tier manages storage, transactions, and integrity.

Concept / Approach:
Recognize that “three-tier” explicitly means 1 client-side tier and 2 server-side tiers. Options listing only server layers or only client layers misunderstand the model.

Step-by-Step Solution:
1) Identify the roles: client (UI), application (logic), data (DBMS).2) Match the description that includes exactly these three roles.3) Select the option that states one client layer and two server layers.

Verification / Alternative check:
Reference diagrams for web apps: browser (presentation), application server (logic), database server (data) are the canonical example.

Why Other Options Are Wrong:

• Three server layers / two client layers / three client layers: Misrepresent the distribution of responsibilities.
• Monolithic tier: Opposite of three-tier separation.

Common Pitfalls:
Confusing “n-tier” with mere horizontal scaling of identical servers; tiers describe functional separation, not just server count.

Final Answer:
A client (presentation) layer and two server layers (application and data)