Which of These Determines the Tertiary Structure of a Protein

Multiple Choice

Which of these determines the tertiary 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) The number of hydrogen bonds which are made between neighboring amino acids.
E) Interactions between amino acids separated by significant distances on the protein chain.