想把当前目录中的myfile.txt文件压缩成myfile.txt.tar,则实现的命令是: A: tar<br/>-jvc -f myfile.txt.tar myfile.txt B: tar<br/>-jvx -f myfile.txt.tar myfile.txt C: tar<br/>-jvr -f myfile.txt.tar myfile.txt D: tar<br/>-jv myfile.txt.tar myfile.txt