DRAG DROP
You are developing a WCF service.
You need to configure the web.config file to ensure that metadata is exposed only via the
MEX protocol. You have the following markup:
Which XML elements should you include in Target 1, Target 2, Target 3 and Target 4 to
complete the markup? (To answer, drag the appropriate XML elements to the correct targets
in the answer area. Each XML element may be used once, more than once, or not at all. You
may need to drag the split bar between panes or scroll to view content.)
Answer: 
Explanation:
To my opinion Target4 should be TRUE
https://msdn.microsoft.com/en-us/library/ee530014(v=vs.110).aspx
No – it should be false. Question specifically states the metadata is exposed via MEX only. If you were to set this value to true, the WSDL would also be exposed over HTTP. See http://stackoverflow.com/a/5870270