Introduction:
The French Revolution was a period of radical social and political upheaval in France from 1789 to 1799. It was marked by the end of the Bourbon monarchy, the rise of radical political factions, and the eventual establishment of the First French Republic. In order to understand the king in France at the time of the Revolution, we need to delve into the historical context.

Louis XVI:
The correct answer is option B, Louis XVI. Louis XVI was the king of France at the time of the French Revolution. He ascended to the throne in 1774, succeeding his grandfather, Louis XV. Louis XVI's reign was marked by financial crises, an inequitable tax system, and widespread social inequality. These factors, combined with concepts of Enlightenment and the influence of the American Revolution, contributed to the outbreak of the French Revolution.

Role in the Revolution:
Louis XVI's reign was characterized by his weak leadership and inability to address the economic and social problems of France. He faced mounting pressure from various factions, including the radical Jacobins, who sought to overthrow the monarchy. The revolution gained momentum with the storming of the Bastille on July 14, 1789, which is widely regarded as the start of the French Revolution.

Execution and Aftermath:
As the revolution progressed, Louis XVI's authority diminished, and he was eventually arrested and put on trial for treason. He was found guilty and executed by guillotine on January 21, 1793. The execution of the king deepened the divisions within France and intensified the revolutionary fervor. It also led to the rise of more radical factions, such as the Committee of Public Safety under the leadership of Maximilien Robespierre.

Conclusion:
In conclusion, Louis XVI was the king of France at the time of the French Revolution. His reign was marked by economic and social crises, which ultimately led to his downfall and execution. The French Revolution had far-reaching consequences, including the end of the monarchy and the establishment of the First French Republic.