Answer:
The correct option is:
c. President Jefferson and the Democratic Republican-led Congress authorized the purchase of the Louisiana Territory in 1803, despite the Constitution's lack of instruction on buying land from foreign countries, expanding federal power.
The purchase of the Louisiana Territory was a significant expansion of federal power because it involved a major land acquisition that had not been explicitly authorized by the Constitution. This expansion of territory and jurisdiction had a profound impact on the size and scope of the federal government in the early 19th century.