If I am not wrong, I believe the answer is Producers. The reason as to why I say that producers is the answer is because in every food chain, there needs to be a base. That base is what provides the starting energy that will later on move up in the food chain.
A l,ll,lll and lV would be the answer because a eukaryote is an organism with complex cells, or a single cell with a complex structures. In these cells the genetic material is organized into chromosomes in the cell nucleus. Animals, plants, algae and fungi are all eukaryotes. There are also eukaryotes amongst single-celled protists.
I believe the best answer is the gallbladder.
I hope this helped