Final answer:
James Madison despaired for the Constitution's viability due to the omission of a bill of rights protecting civil liberties, which was a major concern for many and led to significant debate before the eventual ratification of the Constitution with the Bill of Rights included. Therefore correct option is A
Step-by-step explanation:
The rejection of the convention on one point that caused James Madison to really despair for the Constitution's viability was a bill of rights that protected civil liberties. The Constitution initially did not include a Bill of Rights, and this was a significant concern for many at the time, including prominent figures like George Mason. The lack of explicit protections for individual rights and freedoms in the face of a strong central government was seen as a potential threat to those liberties. Despite James Madison's efforts and the addition of the Bill of Rights as the first ten amendments to the Constitution, this initial omission was a major sticking point that nearly prevented its ratification.