What legislative activity must be passed and signed before any federal agency can incur obligations from the U.S. Treasury?

The correct response is the Appropriations Bill. This is the legislative vehicle that allows federal agencies to incur obligations and make expenditures from the U.S. Treasury. Before any federal agency can use money from the Treasury, Congress must first pass an appropriations bill that specifies how much funding is allocated for specific purposes.

The appropriations process involves several steps, including the formulation of the President's budget request, the approval of the budget resolution by Congress, and subsequent actions regarding appropriations bills for various government functions. Only once these bills are passed and signed into law does an agency acquire the legal authority to access and spend the funds.

In contrast to the appropriations bill, an Authorization Act establishes programs or policies but does not provide the actual funding necessary for implementation. Tax legislation and the budget resolution also play critical roles in the federal budget process but do not directly authorize spending from the Treasury, which is exclusively the focus of appropriations. Therefore, the answer aligning with the requirement for agencies to incur obligations from the U.S. Treasury is indeed the Appropriations Bill.