Which of the Following Describes a Protein

Which of the following describes a protein?

A) A molecules composed of three small sugar molecules.
B) A relatively small, water-soluble molecule that contains either a ketone or an aldehyde functional group.
C) A large biological polymer composed of amino acids.
D) And ester of phosphoric acid where one or more of the ionizable hydrogen atoms has been replaced by an R group.
E) A tri-ester of glycerol where each of the hydroxyl-group hydrogen atoms in glycerol has been replaced by the alkyl group of a relatively long hydrocarbon chain carboxylic acid.