Final answer:
The flaw in the electoral system of the nation revealed by the election of John Adams was unequal representation in the Electoral College. The option (D) is correct.
Step-by-step explanation:
The election of John Adams revealed the flaw in the electoral system of the nation as unequal representation in the Electoral College.
The Electoral College is the process through which the President is elected in the United States. Each state is assigned several electors based on its representation in Congress, which is the combination of the number of Senators and Representatives. The flaw in this system is that some states have more representation in the Electoral College than others, leading to unequal influence in the outcome of the election.
In the election of 1800, John Adams won the presidency despite receiving fewer popular votes than Thomas Jefferson. This demonstrated the flaw in the Electoral College system, where the winner-takes-all allocation of electors in each state can lead to a candidate with a minority of the popular vote winning the presidency. Therefore, option (D) is correct.