Correct answer is -iv) Document Data Model
Document Data Model data model is used in MarkLogic.The basic unit of organization in MarkLogic is a document. These can be encoded in JSON or XML.MarkLogic stores Documents as compressed trees, based on the well-known XPath Data Model. This model is sufficiently featured to represent all sorts of documents, including plain-text and JSON.The advantage of storing documents in XML format is that you can query the tree structure, using XPath expressions such as /doc/title. And with MarkLogic, you can perform searches that are aware of and can be qualified by this tree structure.