Final answer:
The US Department of Commerce (USDC) is responsible for overseeing the voluntary inspection and grading of fish and fish products, which is distinct from the roles of the FDA and USDA.
Step-by-step explanation:
The correct answer to the question, Which of the following agencies oversees voluntary inspection and grading of fish and fish products? is C. USDC (US Department of Commerce). This department is responsible for promoting economic growth and includes agencies that have the authority to regulate various aspects of trade and commerce, including the inspection and grading of fishery products. This is distinct from the roles of other agencies such as the FDA, which oversees food safety and the regulation of food products, and the USDA, which is responsible for the inspection and grading of meat, poultry, and egg products. The Department of Treasury, on the other hand, is not involved in food inspection but rather handles the financial and monetary matters of the government.