How do kitten umbilical cords work in utero?

Hi, my cat recently had kittens so I was just thinking about it some and got curious. Do they have one big umbilical cord that connects to one placenta, and then splits off into 6 cords to each kitten? Do they each get their own smaller placenta? Is there one placenta with 6 individual cords coming from it? (So not like the first option, which would be one cord that splits off, like frayed wire)

Just got curious and now I need to know lol