The correct answer is B, as the Tokugawa shogunate was a dynasty created after Ieyasu defeated all the warlords and united Japan under one rule.
The Tokugawa shogunate was the third and last shogunate to hold power throughout Japan; the previous two were the Kamakura shogunate (1192-1333) and the Ashikaga shogunate (1336-1573). This shogunate was established by the shogun Tokugawa Ieyasu.
During the period of the shogunates there was a species of military dictatorship submitted specifically to the emperor of Japan. The shogun, who became the general commander of the armed forces of Japan, had the military and political power of the country; while the emperor was assigned spiritual and religious power, as a link between people and gods, and nominal power in the Imperial Court of Kyoto.
Fifteen shoguns administered the power of the Tokugawa clan and the country for 264 years, subordinating the other clans in exchange for a secondary or provincial power. In this period the clan is known for adopting a policy that centralized and unified the country devastated by the wars of the old Sengoku era, and managed to establish a class system in Japanese society. It is also known for adopting a position of absolute isolation from the rest of the world (sakoku), which led to the prohibition and expulsion of foreigners and the elimination of external influences by any means. Such was the case of the extermination of Christians during the shogunate, as well as other drastic resolutions, whose purpose was to maintain the balance of power in Japan.
The nominal power of the shogunato was in the city of Edo (present Tokyo), unlike the imperial power, established in Kyoto. Thus, this period of rule of the Tokugawa shogunate is known as the Edo period or Tokugawa period.
This period ended under multiple pressures with the surrender of the power of Tokugawa Yoshinobu to Emperor Meiji, on November 9, 1867. Thereafter the shogunate was abolished and the emperor gained the military and political power of the country, unleashing the Meiji Restoration that would transform the country radically during the rest of the 19th century.
