Final answer:
The Office of Thrift Supervision was responsible for overseeing savings and loan institutions. However, this agency has been dissolved since 2011, and its functions were transferred to other federal agencies.
Step-by-step explanation:
The Office of Thrift Supervision (OTS) was responsible for overseeing certain financial institutions within the United States. Specifically, the OTS oversaw savings and loan institutions, also sometimes called 'savings and loans' or 'thrifts'. These institutions receive deposits and make loans, much like banks, but historically they were focused largely on housing-related loans.
It should be noted, however, that as of 2011, the responsibilities of the OTS have been transferred to the Office of the Comptroller of the Currency (OCC), the Federal Reserve Board, and the Federal Deposit Insurance Corporation (FDIC) due to the dissolution of the OTS under the Dodd-Frank Wall Street Reform and Consumer Protection Act.
Therefore, the correct answer to the question is: c. savings and loan institutions.