A: Following the patriarchal enfeoffment system in ancient China, there appeared a two-level local administrative system of county-county integration. It prevailed in Qin and Han Dynasties. The county system is the embodiment of the ancient centralized system in the local regime, which was formed in the Warring States period. There were already counties in the Spring and Autumn Period. Counties in the Spring and Autumn Period can be divided into two types: the counties in Chu and Qin were directly subordinate to the monarch; Most counties in Jin and Wu were the fiefs of the Qing doctor. Both of them directly belong to the capital of the monarch and have the function of frontier towns. Chu Wuwang destroyed the state power and changed it into a county, which was the beginning of establishing a county. In the late spring and autumn period, the county system began to be gradually implemented in the mainland. So a is wrong.

B: The county system fundamentally negates the enfeoffment system, breaks the situation of enfeoffment system and separatist regime since the Western Zhou Dynasty, strengthens the management of local governments by the central government, helps prevent separatist regimes from splitting, and effectively safeguards national unity. Unlike the enfeoffment system, county orders and county orders were directly appointed and removed by the emperor. So b is correct.

C: During the Warring States Period, counties were widely set up, and it was transformed into a county system with bureaucratic system as the local political power. So c is correct.

D: After the reunification of Qin, the county system spread all over the country. Sima Qian said that Qin Shihuang divided the world into 36 counties, and the Book of Jin thought it was added after unification, with as many as 40 counties, and Wang Guowei and others thought there were more than 40 counties. During the Western Han Dynasty, new counties were established continuously. According to the records in the early Yuan Dynasty, there were 103 counties in China. So d is correct.

Conclusion There is something wrong with the topic, A is wrong and BCD is right.