Which of the Following Describes a Steroid

Which of the following describes a steroid?

A) A group of molecules that have a special grouping of 5- and 6-member rings in common.
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D) And ester of phosphoric acid where one or more of the ionizable hydrogen atoms has been replaced by an R group.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 group of molecules that make up a lipid bilayer.