DW Question & Answer Pro is an all-time favourite question & answer plugin for WordPress. Your WordPress site will have a full-featured question & answer section like StackOverflow, Quora or Yahoo Answers.

Demo:

https://tinyurls.ca/V51kQ

https://www5.zippyshare.com/v/24oj2YFC/file.html

https://mega.nz/#!uj4gwKAY!z0sg1bX4yw9X0I7jiUK-alGEBDrkjkxpcU3TUKqdYkM

http://uploadseed.com/vx