שאלה | What is the relation between collections, documents, clusters, and databases in MongoDB?

What is the relation between collections, documents, clusters, and databases in MongoDB?

		Clusters contain several databases, databases contain several collections, collections contain several documents
		Databases contain several clusters, clusters contain several collections, collections contain several documents
		Databases contain several clusters, clusters contain several documents, documents contain several collections
		Clusters contain several databases, databases contain several documents, documents contain several collections