Which of These Determines the Quaternary Structure of a Protein

Which of these determines the quaternary structure of a protein?

A) The sequence of amino acids.
B) The ratio of acidic amino acids to basic amino acids.
C) The number of alpha helices and pleated sheets along the axis of the protein.
D) Two or more subchains of amino acids held together by attractions between the chains.
E) Interactions between amino acids separated by significant distances on the protein chain.