Hi everyone, thanks for your comments I will take notes next time

Good day everyone. I need your help. I went for my US Visa appointment today but I was denied. Here's my experience.
VO: Good morning
Me: Good morning
VO: Let me have your passport
Me: Yes ma
VO: Why do you want to travel
Me: To visit my sister and also to celebrate my birthday
VO: Are you married
Me: Yes ma with 3 kid
VO: where are your children
Me: One is in Nigeria married and the other two are in UK
VO: Have you been out of country
Me: Yes ma
VO: Where
Me: UK
VO: What do you do
Me: I'm a business woman
VO: What do you earn
Me: I earn N600,000
VO: You are sponsoring yourself
Me: Yes ma
That was all. I will like to know where I've missed it and advice for when I reapply.