It looks like you have not done the required homework to ensure you're adequately prepared for when you go in for your interview. Your interview location is Paris, right? (based on one of your previous posts). The
US Paris Embassy's website has a lot of useful information which you should have been aware of by now, one of which addresses the need for all applicants to be prepared to demonstrate they're unlikely to become a public charge by presenting an
Affidavit of Support or Employment Letter. For DV cases and all other applicants (not listed) under the
Assemble the required documents section, it says:
"All
other applicants, including K-1 (fiancé/e) applicants must show evidence that they are not likely to become a public charge while in the United States. Use of the form I-134 is an efficient way to provide this information to the Consular Officer."