Answer: D
The publication number is the number used by the State Intellectual Property Office when the patent is published during the patent application process and before patent authorization is obtained. The announcement number is the number given when the patent right is granted. my country's patent publication number and announcement number are composed of four parts: "country number + classification number + serial number + identification code". At the national level, two-letter country codes are often used to identify countries, such as "AT" for Austria, "CN" for China, "EP" for Europe, and "US" for the United States.