A Controversial Field Experiment (Kramer, Guillory, and Hancock, 2014) Manipulated

A controversial field experiment (Kramer, Guillory, and Hancock, 2014) manipulated people's Facebook newsfeeds in what way?

A) Some users saw more positive posts in their newsfeed, while others saw more negative posts in their newsfeed, which influenced the emotional content of the users' posts
B) Some users saw more posts from members of social outgroups while others saw more posts from ingroup members, which altered their social identities and their associated emotions
C) Some users saw more mentions of topics related to intergroup conflict, while some users saw more neutral content, which altered their intergroup anxiety
D) Some users saw more posts with emojis, while some users only saw posts with text, and the users