Last year in March I wanted to visit my girlfriend at the time but my entry to US was rejected under INA section 217 212(a)(7)(A)(i)(I) which says Inadequate Documentation. However, main reason why they rejected me, because last time on VWP I said that I engaged in unauthorized employment (they kept asking, so I didn't want to lie and get ban of 5 years).
Now I am close to K-1 visa interview stage and having some nervous time. So my question is, during the K-1 interview if they ask why I was rejected entry, should I say because of inadequate documentation or that because on my last trip I worked illegaly on ESTA?
I know that I can't lie during the interview and be honest, but saying inadequate documentation feels like not being completely honest and saying about working illegaly feels like some kind of red flag and they won't approve me.
I would appreciate any help or experience.