In the Anthem Blue Cross Breach, Where 80 Million Names

In the Anthem Blue Cross breach, where 80 million names, birthdays, social security numbers, etc., were stolen, the hackers got in by:

A) Breaking into the building where they were stored
B) Obtaining passwords of five or more high-level employees
C) Making phone calls to insiders posing as IT people needing to log into their accounts
D) Emailing each of the 80 million patients asking for their private information
E) Recovering patient records from a large recycling bin