Parents of US citizen Kids(Under 12 year old)- N type visa or B1/B2

Hi There,

We are the parents of US citizen kids(11 years, 10 years). I was on h1b and my wife was on H4. We came back to India in 2014.
Now Kids grown up, we like to visit USA for a month to show my kids their birth place.
Not sure what type of Visa we need to apply B1/B2 or under N “child of n8 n9”.
what are the documentation requirement for me and for my wife to get visa stamped and travel with our kids and come back after a month.