It is the popular term for advanced Internet technology and applications including Blogs, Wikis, RSS and social book marking.
Tim O'Reilly is generally credited with inventing the term, following a conference dealing with next-generation Web concepts and issues held by O'Reilly Media and MediaLive International in 2004.
Both statements are correct. Web 2.0 encompasses advanced technologies (blogs, wikis, RSS, social bookmarking) as mentioned in A. Tim O'Reilly is widely credited with popularizing the term after the 2004 O'Reilly Media conference on next-generation web concepts, making B also true. The conference helped crystallize Web 2.0 as a concept.