Answer:
I'm afraid there is an error in your assertion. Let me clarify:
Assertion (A): The newly elected assembly of Jacobins was called the National Convention (not just "Convention").
This is correct. The National Convention was the first French assembly elected by universal male suffrage. It governed France from September 20, 1792, until October 26, 1795, during the most critical period of the French Revolution.
Reason (R): It abolished the Monarchy and established France as a republic.
This reason is also correct and supports the assertion. The National Convention did indeed abolish the monarchy on September 21, 1792, officially ending the Kingdom of France and establishing the French First Republic.
So in summary:
The assertion is mostly correct but missing the full name "National Convention."
The reason accurately supports the assertion.
The National Convention was a pivotal event in the French Revolution, marking the transition from a constitutional monarchy to a republic and setting the stage for the Reign of Terror and the eventual rise of Napoleon Bonaparte.