50.What can we infer from the passage？
(A)The choices of social media by young and old American adults will converge eventually.
(B)Facebook stands firm as the top choice of social media across a wide range of demographic groups.
(C)More and more people are using Twitter as President Donald Trump likes it so much.
(D)New landscape of social media may be emerging as groups across different demographic backgrounds are now using different kinds of social media.