How Did the Fed Contribute to the Recent Banking Crisis

How did the Fed contribute to the recent banking crisis?

A) As the regulator of monetary policy,the Fed kept interest rates suppressed.
B) As the regulator of monetary policy,the Fed ignored the warnings of Moody's and other bond rating agencies.
C) The Fed required banks to create adjustable rate mortgages with interest rates significantly higher than those attached to fixed-rate mortgages.
D) The Fed encouraged home ownership.