Which of the following commands can be used to back up all the files in the current directory and co

Which of the following commands can be used to back up all the files in the current directory and compress them?

A.
tar -cvf – * | gunzip > backup.tgz

B.
tar zcvf backup.tgz *

C.
gtar zcvf backup.tgz *

D.
tar -Zxvf backup.tgz *