RFE: Name mismatch mom's green card

[chinx]

I am applying for my mom's GC and received RFE on name mismatch.
On my birth certificate my mother's name is written as: Parvatiben.
And on my mother's passport her name is written is Parvati.

What documents would I need to address this RFE?

Is a self attested claim from my mom ( who is in US currently enough) to say that "parvati"
 and "parvatiben" are the same person?

 Do we need affidavit for this? How many?

[pontevecchio]

Usually they will mention what sort of evidence they are looking for and what type of affidavit etc. Have they not done this?