Why Was the Election of 1800 a Pivotal Event for Constitutional

Why was the election of 1800 a pivotal event for constitutional developments in the United States?

A) It was the first time presidential elections were conducted under the Twelfth Amendment.
B) Had power not been transferred peacefully, it would have put the integrity of the Constitution in doubt and future politicians would have a prisoner's dilemma of abiding by the rules or reneging.
C) The concerns over the transition of power illustrated the trade-offs between transaction costs and conformity costs.
D) The questions surrounding the peaceful transfer of power raised important questions about the tragedy of the commons and the willingness of the defeated party to use arcane constitutional moves to protect their power.