I am on a B1 visa which expires on Nov 29th 2019. While entering the US on 28th of Sep 2019, the CBP officer stamped my passport saying I can only stay until 29th of Nov 2019, citing the fact that my visa expires on that date. I have an interview to attend on 8th of December 2019. While checking my online I94 record, I found that the date until which I am admitted is 27th March 2020. Which date should I consider as official (the passport stamp, or the online I94. Do I need to apply for I94 extension if I have to stay until december? Do I also need to apply for visa extension?