Knowledge-based systems in Artificial Intelligence: An ______ system includes both a stored knowledge base and an inference engine.

Introduction / Context:
Within Artificial Intelligence, an expert system is a classic form of a knowledge-based system. It encapsulates domain expertise and uses logical reasoning to reach conclusions, provide recommendations, or explain diagnoses similar to a human expert in a narrow field.

Given Data / Assumptions:

• The system uses a knowledge base containing facts and rules.
• It employs an inference engine to apply rules to known facts and derive new conclusions.
• The question asks for the label that matches this architecture.

Concept / Approach:
An expert system = knowledge base + inference engine + user interface (and often an explanation facility). The knowledge base stores if-then rules, frames, or cases; the inference engine performs forward or backward chaining to infer results. This is distinct from a generic management information system (MIS) or a “control” system.

Step-by-Step Solution:

Verification / Alternative check:
AI textbooks consistently define expert systems using these two core components, plus interfaces and explanations.

Why Other Options Are Wrong:

• Centers/control/MIS: do not denote knowledge-base + inference-engine systems.
• None of the above: incorrect because “expert” is correct.

Common Pitfalls:
Assuming any rule-based automation is an expert system; true expert systems target specialized domains and include explanation facilities.

Final Answer:
expert