The Congressional function in which Congress monitors federal agency performance and holds hearings to inquire about agency policies and decisions is oversight.
Explanation:
Oversight is an error that is caused due to carelessness of the person. This kind of error or mistakes is not made intentionally.
Federal agency is a part of government organizations. It is set up specially to serve a specific purpose like financial oversight of industries, national security issue or management of resources. The federal agency is monitored by the Congress. Congress holds the responsibility to appoint the head of the federal agency.