Normal Hemoglobin Is a Tetramer,consisting of Two Molecules of β-Globin

Normal hemoglobin is a tetramer,consisting of two molecules of β-globin and two molecules of α-globin.In sickle-cell disease,because of a single amino acid change,the mutant hemoglobin tetramers associate with each other and assemble into large fibers.Based on this information alone,we can conclude that sickle-cell hemoglobin exhibits

A) altered primary structure only.
B) altered tertiary structure only.
C) altered secondary and tertiary structures;the primary and quaternary structures may or may not be altered.
D) altered quaternary structure only.
E) altered primary structure and altered quaternary structure;the secondary and tertiary structures may or may not be altered.