Dell PowerConnect 7048P Reset to factory?

Hi

I bought one of these units last week but need to know how to reset it including the passwords back to factory defaults - its not clear on the boot menu options whether opton 10 (delete config files) or whether option 13 (reformat and restore file system) is the correct option - can you please advise? Ideally I want to go back to the switch as new out of the box to start with the dell easy setup

Thanks

Anthony