Which of the Statements About Google's Strategy and Competitive Environment

Which of the statements about Google's strategy and competitive environment is true:

A) Brin and Page founded Google in their 20s, following Yang and Filo of Yahoo (also in their 20s) , underscoring just how it is for new comers to create new threats in today's search market.
B) The scale of server farms capable of indexing today's Web represents a significant barrier to entry.
C) Google has invested in proprietary components such as chips and drives, creating a difficult-to-copy barrier to entry to any firm seeking to enter its markets
D) Bing has been gaining significant market share on Google due to Microsoft's successful leverage of existing products (Xbox, Windows Phone, Office, and the Windows operating system) as a default distribution channel for its search.
E) All of the above.