Natera kit registration

Leslie

I got the blood work for my NIOT testing drawn last Thursday and now I’m trying to register the kit. The website asks me to enter the “kit id below” but there are two different numbers, one on the bottom left of the sticker that ends in an “N” and one in the bottom right that ends in a “C”. The website has drop downs for both the n number and the c number in the kit id drop down. Anyone know which is actually the kit number?