URGENT - DS160 form for H4 extension visa “Travel Information" page

[thiyagu]

Hi,
I am Indian citizen residing in USA.
I am extending my H1B and my wife’s H4 status, while I am in USA.
My wife is NOT working.

I got two I-797 form. One for myself (I129 petition for a Nonimmigrant worker) and one for my wife (I539 application to extend/change nonimmigrant status).
My I129 form has one WAC number and my wife’s I539 form has another WAC number.

While filling DS-160 form for my wife (H4 extension), what information do I need to give on “Travel Information” page for “Application receipt / Petition number”

For ‘Principal Applicant Information’ Surname/given name, I gave my name.
But for “Application receipt / Petition number”, do I need to give my WAC # or my wife’s WAC #.

Thanks In Advance