Visitor Visa - B2

I am on H4 and applied for parents and sister's b2 visa at mumbai consulate which got approved today on 5th April 2014.
It was a self sponsored visa . My father sponsored for entire family! Took all the relevant documents as u never know which document they may ask for, along with NOC from his workplace.

Father in govt service
Mother is a homemaker
Sister studying Engg. 3rd year

VO was a lady!

VO asked most of the questions to father like:

Y do u want to go?
Where are you working?
When did ur daughter went to US?
On which visa is ur daughter and son in law?
How long they have been living there?
How many children you have?

Questions to sister:

What r u doin?
When will u be graduating?
Will u work there? No
What are your plans after engg? she said she'll work in india .
Have you visited any other country before? No

Question to mother(Just one question asked):
What do u do maam? Housewife

Thats all VO said ur visa is approved!! They all got 3 years visa not an issue with us as we had read that its very difficult for younger brother sister to get visa ,but they nailed it!!

So all those trying for younger brother and sister don't lose hope just be well prepared.