I think it's C., carrying genetic information.
Leachate
In the MSW (municipal solid waste) landfill, contaminated water from wastes is known as leachate. Leachate is the contaminated liquid (water) produced when percolating liquid, especially rainwater drains through wastes that are placed in a landfill. When the liquid enters wastes, it separates or filters out constituents from the wastes which result in the formation of leachate.
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.