A. For the write operation, only 3 copies will return a successful write response, and the 2 copies that fail to write will not be filled with 0, and will be processed according to the successful writing of the article.

B. For the write operation, only 3 copies return a successful write response, and the 2 copies that fail to write are all filled with 0, and processed according to the successful writing of the article

C. For the read operation, the system only successfully reads 3 copies, and returns 3 copies of the successfully read data, and returns the 2 copies that failed to read with all 0s

D. For the read operation, the system only successfully reads 3 copies, and returns 3 copies of successfully read data, and the 2 copies that fail to be read are recovered by verifying the data