US B1/B2 Visa approved for parents

Context: I am on H1B visa in the US and my parents were planning to visit me next summer. I am from India and they had applied for a B2 visa.

The first question they were asked was my visa status in the US. Once my dad answered that, the officer asked them to produce a copy of my passport and visa/H1B approval notice. I didn’t know they were required to carry this for the interview. My dad said they didn’t have this with them currently.

The interviewer then asked what my dad’s occupation was and purpose of visit (My dad is a government officer). He answered those questions. It was followed with whether I had gone to the US directly for the job or if I did a graduate or undergraduate degree from the US (I have done my masters here).

Finally the officer confirmed if my parents would be able to produce a copy of my passport and visa when they eventually travel to the US. They said yes and the visa was approved right after that.