Which accurately describes the reasons for the development of the Reign of Terror?

Following the beheading of King Louis XVI, France moved to radicalism, including the emergence of Maximilien Robespierre and his use of the guillotine against enemies of the Revolution.

Following the beheading of Robespierre, France moved to radicalism, including the emergence of Jean-Paul Marat’s use of the French army to commit mass murders of the Third Estate.

Following the beheading of Jacques-Pierre Brissot, France moved to conservatism and the emergence of Lazare Carnot as the leader of the coup d’etat against the French Directory.

Following the beheading of Georges Danton, France moved to conservatism and the emergence of Marie Antoinette and her persecution of practicing Catholics and clergy.

A?

I am inclined to agree with you but see:

https://en.wikipedia.org/wiki/Reign_of_Terror

Yes, Option A accurately describes the reasons for the development of the Reign of Terror. Following the beheading of King Louis XVI, France did move towards radicalism, which included the rise of Maximilien Robespierre. Robespierre used the guillotine as a means to execute enemies of the Revolution, leading to a period of mass executions and fear known as the Reign of Terror.