Nub?? 13 weeks 3 days

Had my scan and dated at 13weeks 3 days and little confused on if the white thing at the bottom area is a nub or if I'm looking at something else. To me it looks slightly on the rise maybe? Angled? Then again it also looks too low down to me to be a nub and big?? I have two boys already but never got a nub shot on either of there scans. Really not bothered by gender but I have 2 weeks to my gender scan so just for fun anyone what to take a guess? Will update on the 10th April!!