Which of the following commands displays the contents of a gzip compressed tar archive?

This pipes gzip compression (not decompression) of the archive into tar, which is logically backwards and would not display contents.

The 'tar ztf archive.tgz' command uses the 'z' flag to invoke gzip decompression, 't' to list (table of contents) rather than extract, and 'f' to specify the archive file. This is the standard single-command approach for viewing gzip-compressed tar archive contents.

The 'gzip -d' command decompresses to a file by default rather than stdout, so piping to tar would fail without a '-c' flag, and this two-step approach is not correct syntax as written.

'tar cf' creates a new tar archive rather than listing contents, and it lacks both the 'z' flag for gzip and the 't' flag for listing.