From "Amazon.com." Encyclopedia Britannica. Encyclopedia Britannica Online School Edition. Encyclopedia Britannica, Inc., 2013. Web. 10 Jan. 2013.
'The Kindle Shakes Up Publishing'
In 2009 the company introduced its first publishing line, AmazonEncore, dedicated to popular self-published and out-of-print books. It also let individuals publish their own e-books. In 2011 its e-book ambitions led to the launch of Amazon Publishing with the intent to develop and publish its own titles. That year Amazon.com announced that Kindle e-books were outselling all printed books. While many book publishers continue to derive significant revenue through sales at Amazon.com, the company is no longer considered by publishers merely as another bookseller. It is now also a major competitor in their industry.

What is the central idea of this passage? (3 points)

a
E-books now outsell printed books, according to Amazon.

b
Amazon offers a way for individuals to publish their writings.

c
AmazonEncore specializes in books that are hard to find or out of print.

d
Amazon has transformed itself from a seller into a publisher.