The correct answer is A) it contradicted Jefferson's constitutional principles.
Before this purchase, Jefferson was an advocate of a strict interpretation of the US Constitution. This means he believed that that the constitution should be followed exactly how it is written. Jefferson did not believe in "implied powers." Simply put, if the power to take an action was not explicitly given to the federal government in the Constitution, than the federal government could not take that action.
The purchase of the Louisiana territory contradicts this belief, as nowhere in the Constitution does it say that the president has the power to buy land from a foreign country.
