Why Does Congress Conduct Oversight into Federal Bureaucratic Agencies

Why does Congress conduct oversight into federal bureaucratic agencies?

A) to check the power of the agencies that have been granted additional authority
B) to make sure those agencies are following the rules specifically outlined by Congress on legislation
C) to be sure that the agencies are acting in the interests of lobbyist groups instead of the people
D) to provide additional resources for the agency to successfully form and implement legislation