Nub or cord?

Irene

I swore I would never post about this but I’m driving myself insane trying to figure it out lol this is at exactly 13 weeks at my NT scan. I see a nub in some pics but it seems kind of big? In one pic you can kind of see the core is in that area so I’m not sure Lol then I see two nubs... and then no nub.

What are y’all a opinions? Thank you!