Who is considered Petitioner on Ds-260 Immigrant visa form for approved I-824 follow to join application?

My I-824 follow to join application for my wife was recently approved and now I need to submit DS-260 form to National Visa Center for my wife’s immigrant visa.

I am confused on one of the questions on the DS-260 form and need a small help. In the Petitioner section of the form there is a question “Petitioner is my” and the options given are “Employer”, ”Prospective Employer”, “Self” and “Other”.

What do I need to select here?
Why is “Spouse” option not available?
Am I not the Petitioner?
Or since this is based on follow to join based on my original i-140 and I-485 applications, is my Employer who sponsored my green card the petitioner?

Yes

Petitioner: A U.S. citizen or lawful permanent resident family member or employer (or the employer’s agent) who files a family-based or employment-based immigrant visa petition with USCIS.

Your I-824 follow to join application for wife is based on employment-based immigrant petition.
Thus, employer should be petitioner since I-824 in this case is just by-product petition based on your employment-based petition.

답변 감사합니다. 그럼 I 864 Affidavit 과 재정서류는 nvc 에 보낼 필요가 없는거죠?