The correct option is C
The Republic of China was a sovereign state in East Asia, which occupied the territories of modern China, and part of its history was Mongolia and Taiwan. It was founded in 1912, after the Qing Dynasty, the last imperial dynasty, was overthrown in the Xinhai Revolution. The first president of the Republic, Sun Yat-sen, served only briefly before handing over the post to Yuan Shikai, former leader of the Beiyang army. Yuan tried to reinstate the monarchy, before resigning after the popular unrest. After the death of Yuan in 1916, the members of the cliques of the old army of Beiyang claimed their autonomy and fought each other. During this period, the authority of the republican government was weakened by the restoration of the Qing government.
The warlords exercised their control throughout China on several occasions in the history of this country, but the most notable period was during the Xinhai Revolution, when numerous provinces rebelled and declared themselves independent of the government of the Dynasty Qing in 1911 and especially in the period from after the death of Yuan Shikai to the Northern Expedition in 1927. This period of Chinese history has been called the "era of warlords". It is at this time that the term was coined.