Why Did France's Entry into War with Austria in 1792

Why did France's entry into war with Austria in 1792 have an immediate radicalizing effect on the Revolution?

A) Most French citizens had no desire to go to war against their great ally, so massive protests sprang up throughout the countryside attacking revolutionary leaders.
B) Realizing they had Austria behind them, millions of French citizens joined a huge counterrevolutionary movement in support of the monarchy.
C) When the French armies proved dreadfully unprepared for battle, the authority of the Assembly was challenged, and angry crowds instigated more radical political change.
D) With the support of the Austrian army, Louis XVI made another unsuccessful escape attempt, leading revolutionaries to call for his execution.