Social Media First Began to Get More Professional and Offer

Social media first began to get more professional and offer more to users

A) just after its invention phase in the early 1990s.
B) at the turn of the twentieth century,during its industrialization phase.
C) when Apple launched the first App Store.
D) in the last few years,during its entrepreneurial phase.
E) in 2011-2012,when the market became flooded with smartphones.