Final answer:
Congress controls the bureaucracy most directly by performing legislative oversight through hearings, which is option C. They question agency leaders and manage the federal budget, including each agency's budget, and pass laws affecting the bureaucracy.
Step-by-step explanation:
The bureaucracy is controlled by Congress in several ways, but when considering the options provided, the most accurate answer is C. Congress performs legislative oversight through hearings. These hearings allow Congress to question the leaders of various bureaucratic agencies about their activities and budgets, as well as to investigate any significant mistakes or problems. While the president appoints the heads of cabinet departments and many independent executive agencies, these appointments require Senate confirmation. Additionally, Congress manages the overarching federal budget, which includes the budgets of individual agencies. Though not through appointments, Congress can exert influence over the bureaucracy by controlling its finances and by legislating changes in its structure or functions. Therefore, Congress's ability to perform legislative oversight through hearings is a significant tool for controlling the federal bureaucracy.