What are the main uses of XML?

XML is used for data exchange between systems, storage of application configurations, representation of electronic documents and definition of web service interfaces.
XML is only used for data exchange between similar systems.
XML is only used for the representation of electronic documents.
XML is a closed standard that cannot be used in different applications.
a) Only statement I is correct.
b) Statements I and II are correct.
c) Statement I is correct and statements III and IV are incorrect.
d) Statement I is correct and statements II, III and IV are incorrect.