Answer:
A. It was overthrown by invading Mongol tribes in 1279.
Explanation:
The Song Dynasty was a ruling dynasty in China between the years 960 and 1279; that happened to the period of the Five Dynasties and the Ten Kingdoms and was succeeded by the Yuan dynasty. It was the first government in world history to use paper money, and the first Chinese government to establish a permanent navy. This dynasty also saw the first known use of gunpowder, as well as the first discernment of the true North using the compass. The Southern Song dynasty considerably strengthened its naval force, in order to defend its waters and borders and carry out maritime missions abroad.
In 1234, the Jin Dynasty was conquered by the Mongols, who took control of northern China, maintaining precarious relations with the Southern Song. Möngke Kan, the fourth Great Khan of the Mongol Empire, died in 1259 while besieging a city in Chongqing. His younger brother, Kublai Khan, was proclaimed the new Great Khan, although his appointment was only partially acknowledged by the Mongols in the east. In 1271, Kublai Khan was proclaimed Emperor of China. After two decades of sporadic fighting, the armies of Kublai Khan conquered the Song dynasty in 1279. China was once again unified under the Mongol Yuan dynasty (1271-1368).
