Animalia and Fungi I believe.
My best guess would be c because b makes no since we as humans do not have photosynthesis and are considered living organisims, d is also wrong because the brain requires oxygen, and its not a because the brain is made of cells.
Sterile water is most often used
Complex molecules are made up of other elements bonded with carbon. Carbon is able to bond with other molecules so easily because it has four valence electrons.