Explain ACID and BASE properties, and also explain inheritance and abstraction with a concrete example.
Implement explain_concepts(topic), where topic is one of "acid", "base", "inheritance", "abstraction", or "all". Return a concise explanation string for the requested topic. For "all", return one string covering all four concepts and include a concrete inheritance and abstraction example. Return an empty string for unsupported topics.
def explain_concepts(topic):