Which of the following is one of the notable achievements of early china?
a. a complex system of writing
b. a single spoken language
c. cotton textiles
d. copper ore technology

One of China's notable achievements is A. a complex system o writing.

Its ancient form was originated from the practice of divination, finding the first inscriptions on pieces of bones and tortoiseshell. One of the facts that makes it notable is that, until relatively recently, Chinese writing was used more widely than alphabetic writing systems.

In its beginning, Chinese writing was based on the pictures of objects which represented concepts (logographic), to signs representing the concepts themselves.

b) the confederacy had to pay all union war expenses.