Why did Congress reorganize the intelligence community and create a new position known as the Director of National Intelligence?

a. The director of the Central Intelligence Agency needed additional authority to combat the growing threat posed by weapons of mass destruction.
b. The September 11, 2001, terrorist attacks revealed flaws in the way the U.S. intelligence community operated.
c. There was a need for the decentralization of authority within the intelligence community to prevent competition among agencies.
d. The previous organizational structure of the intelligence community encouraged the various agencies to do too much of their work collaboratively.

b