I think the correct answer would be A. The yolk sac becomes the placenta. It is membranous sac that is attached to the embryo. It provides all the nutrition and the blood cells needed by the embryo. It is also called the umbilical vesicle.
Jellyfish are forever but fish ain't.
Plus, jellyfish have those tentacle like things attached to thier body and you might confuse em for octopus for that very reason..
but you should really evade confusing em as an octopus cuz octopus might take it as an insult and the next thing you know will be a Kraken taking your house down.. which is pretty tragic :'(
Chicken with feather or depending on what you cross breed it with
For real lo people just be putting anything