A$)$ Explain about backward chaining in propositional logic.

B$)$ In a complex diagnostic system for a spacecraft, use backward chaining to identify the root cause of an anomaly by tracing back from observed symptoms to potential subsystem failures.

C$)$ Given a knowledge base representing a multi$-$agent negotiation system, use backward chaining to determine the optimal negotiation strategy for a specific agent to reach an agreement while maximizing its utility

D$)$ Create a propositional logic knowledge base for a medical expert system. Use

backward chaining to diagnose a patient's illness by starting with observed symptoms and working backward to identify the underlying medical condition. E$)$ Consider a complex legal expert system that uses propositional logic. Use backward

chaining to determine the legal implications of a set of facts and evidence, leading to a legal conclusion.