Napolean Bonaparte rose to power as a military dictator in culmination of the following circumstances 1) The fall of the Jacobin Govt. and the subsequent ascendency of wealthier middle classes. 2) Introduction of a new constitution with the provision of two legislative councils along with denial of the right to vote to non-properetied classes. 3) Appointment of a directory as an executive made up of five members in order to prevent concentration of power in one person like Robespierre during the Jacobin Rule. 4) Political instability caused by the clashes among the Directors and the legislative councils who sought to dismiss them.

The correct answer is option 'C': Political instability of the Directory.

Explanation:
The rise of Napoleon Bonaparte can be attributed to several factors, including the fall of the Jacobin government, Robespierre's Reign of Terror, political instability of the Directory, and nationalist forces. However, the most significant factor among these was the political instability of the Directory.

1. Fall of the Jacobin government:
The fall of the Jacobin government, which was associated with the radical phase of the French Revolution, created a power vacuum and an opportunity for new leaders to rise. This period was marked by the Reign of Terror, where thousands of individuals were executed, leading to social unrest and dissatisfaction with the revolutionary government.

2. Robespierre's Reign of Terror:
Robespierre's Reign of Terror was a period of intense political repression and violence, aimed at eliminating counter-revolutionary forces and securing the revolution. However, this excessive use of violence and the Committee of Public Safety's authoritarian rule led to discontent among the people, as well as within the revolutionary government itself.

3. Political instability of the Directory:
The Directory was the government that came after the fall of the Jacobin government. It was a weak and ineffective government characterized by corruption, economic instability, and political infighting. The Directory faced numerous challenges, including financial crises, military defeats, and popular dissatisfaction. This political instability created an environment where ambitious military leaders like Napoleon could seize power.

4. Nationalist forces:
Nationalism played a significant role in the rise of Napoleon. The French Revolution had spread ideas of nationalism and patriotism, and Napoleon capitalized on this sentiment. He presented himself as a strong, nationalistic leader who could restore stability and defend French interests abroad. This appeal to nationalism helped him garner support from the people and the military.

In conclusion, while all the factors mentioned - fall of the Jacobin government, Robespierre's Reign of Terror, nationalist forces - contributed to the rise of Napoleon, the political instability of the Directory was the most significant factor. The weak and corrupt government provided a fertile ground for Napoleon to assert his authority and eventually seize power, leading to the establishment of the Napoleonic Empire.