Which of the following statements are true according to our material?

Group of answer choices

$($A$)$ Amazon Mechanical Turk, YouTube, Twitter, Wikipedia represent different crowdsourcing platform.

$($B$)$ Youtube is an incentive based crowdsourcing platform.

$($C$)$ Amazon Mechanical Turk and Wikipedia are two voluntary crowdsourcing platforms.

$($D$)$ A crowd sourcing platform will ask crowd to carry out human intelligent tasks and perform crowd answer analytics to identify and integrate crowd intelligence with machine intelligence.

$($E$)$ How to put human in the loop for crowd answer analytics is one of the key differentiation factors for crowd computing services.