You could use cp (with the -r option so that it will recursively grab directories) for this. tar is usually if you want to backup the data into a single file in case it needs to be restored at a later date, or you are moving data to a different machine. To copy your directory tree, you'd just
cp -r ~/a/b/c/* ~/backup/option
Assuming that you only want to backup from that c directory and down. Note that if you omit the /* from the source name, you'll end up with a ~/backup/option/c directory which may or may not be what you want. If you want to do from ~/a down, then it would be just
cp -r ~/a/* ~/backup/option
Tryto keep it simple. In this case, there is no real need to use tar when a simple cp will do. I tried to figure out how to tar/untar in the same command using a pipe, and couldn't figure it out. And really, if it can be done with a single command with no pipes, that will be your best bet, especially should something go wrong ... less steps to look through.