In 2007, there was a crisis in the market for securitized mortgages. Some contributing factors were:

• A. bursting of the housing bubble, excessive extension of credit to subprime borrowers, excessively restrictive oversight of banks by the Fed, Office of Thrift Supervision and FDIC.
• B. unsavory practices by mortgage lenders, bursting of the housing bubble, and excessive retention of mortgages by the banks which originated them
• C. unsavory practices by mortgage lenders, bursting of the housing bubble, and excessive extension of credit to subprime borrowers
• D. bursting of the housing bubble,excessive provisions of the Dodd Frank Act, unsavory practices by mortgage lender s