Carbon is the only element that can form so many different compounds because each carbon atom can form four chemical bonds to other atoms, and because the carbon atom is just the right, small size to fit in comfortably as parts of very large molecules.
Maybe A, B, and D, this could be wrong but my best guesstimate
It happens in glycolysis. It gets broken down into two pyruvates and it happens in the cytoplasm.
Answer: To make protein and store hereditary information
Explanation: