Answer :

Because none of the delegates were authorized by their 
state governments to make changes to the Articles, especially  
to change it all together. When the delegates realized 
that the best thing to do was to make a new national government, 
they decided to keep their arguments and debates secret to keep outside 
interference.

The correct answer is:  

To revise the Articles of Confederation.  

The delegates’ biggest concern was that if the press leaked their discussions to the public, it would portray a fragmentary and misleading idea of what they were trying to achieve. Therefore, the convention delegates agreed to shield themselves from the publication of their proceedings by voting to hold those actions a total secret from all outsiders, including the press.