An inference engine is:

An inference engine is a crucial component of an expert system, functioning primarily as the mechanism that applies logical rules to the knowledge base to deduce new information or solve problems. In this context, the correct answer highlights that the inference engine utilizes strategies such as forward chaining or backward chaining to navigate through the rule base.

Forward chaining starts with the available data and applies rules to infer conclusions, moving from premises to conclusions, which is useful in situations where conclusions need to be drawn based on known data. Backward chaining, on the other hand, begins with the goal or hypothesis and works backward to determine what data is needed to support that conclusion, often employed in scenarios where specific answers or solutions are sought.

This capability to systematically search through the rule base using these strategies enables the inference engine to effectively mimic the decision-making abilities of a human expert, making it a fundamental part of expert systems. Understanding this role helps in grasping how knowledge is applied to generate solutions within artificial intelligence domains.