US Immigration from Dominican Republic

Hi,

I'm new to the forum; I have ben trying to find some help at not avail so far.

I'm a L-1A visa holder; my 15-year-old daughter is a L-2 visa holder. We have been in the States for a little over three years now. I recently got married to my wife; we had been together for over a year and engaged for a few months. I have been reading and educating myself about the Adjustment of Status process; I believe I have it down for the most part - all forms and evidence we need but there's something that's confusing/misleading me:

1. I filled form I-485 for my daughter
2. I cannot find anywhere what 'Application Type or Filing Category' (Part 2.) I have to select for her; I only know she's a 'Derivative applicant'
3. On page 23 of the I-485 instructions, 'Additional Instructions for Family-Based Applicant' under the 'Immediate relative of a U.S. citizen (Form I-130, Petition for Alien Relative)' it says: "Derivative applicants are not allowed in this category"

If I'm not mistaken, my daughter is my wife's stepdaughter now. According to what I have read, my daughter qualifies as a child of my wife but given my daughter is a 'Derivative Applicant', my question is, what is the Application Type or Filing Category I should select or enter for her? This is the only thing that's holding us off from submitting the petitions.

Any help or guide you can provide is appreciated.

Thank you.