What Explains the Reason for the Historically Very Low (1/3

What explains the reason for the historically very low (1/3% to 1/2%) limit on allowance for doubtful accounts in China?

A) The primary customer in China was the government,which was presumed to have very good credit.
B) This is the international accounting standard for companies operating in eastern Asia.
C) Prior to being admitted to the World Trade Organization (WTO) ,China was required to reduce its bad debt level.
D) all of the above