[单选题]关于xGW(PDSN) ftp根目录的配置,以下命令正确的是()。
Which of the following commands is correct about setting the FTP root directory in the xGW(PDSN)? ( ) A.ftp-server top-directory /sysdisk0 B.ftp-server top-directory /sysdisk0/ C.ftp-server root-directory /sysdisk0 D.ftp-server root-directory /sysdisk0/