Which of the following geographic features most likely hindered the byzantines from expanding north of italy?

Why is the federal reserve managed under the oversight of the federal government? the fed is responsible for printing and coining money.the fed is responsible for collecting income taxes.the fed is responsible for the government’s money.the fed is responsible for paying off government debt.(the first option isn't correct i tried that one)edit: the answer is the fed is responsible for the government’s money.