Thomas Jefferson was concerned that the treaty formalizing the Louisiana Purchase

A. would place an unfair tax burden on American citizens.
B. might be unconstitutional.
C. would invite French hostility.
D. was clearly illegal.

B

http://www.sparknotes.com/biography/jefferson/section14.rhtml

To determine why Thomas Jefferson was concerned about the treaty formalizing the Louisiana Purchase, we can look into historical context and Jefferson's viewpoints.

The Louisiana Purchase refers to the acquisition of the Louisiana Territory by the United States from France in 1803. Thomas Jefferson, being the president at the time, played a significant role in the deal. While the purchase was viewed as a notable achievement for the young nation, there were particular concerns that Jefferson had regarding the treaty.

B. might be unconstitutional.

One of Jefferson's concerns was that the treaty might be unconstitutional. This concern emerged from Jefferson's strict interpretation of the United States Constitution. Since the Constitution did not explicitly grant the federal government the power to acquire new territories, Jefferson questioned the legality of the purchase. He faced a dilemma between his desire for the land and his commitment to adhering strictly to the Constitution's enumerated powers.

To find this answer, you can consult primary sources such as Jefferson's letters, speeches, or writings about the Louisiana Purchase. Additionally, biographies or historical accounts of Jefferson's presidency can provide insights into his concerns and reasoning.