The Fact That When a Deoxyhemoglobin Crystal Is Oxygenated It

The fact that when a deoxyhemoglobin crystal is oxygenated it breaks up into fragments supports the statement that

A) hemoglobin is a tetramer.
B) oxyhemoglobin and deoxyhemoglobin have different conformations.
C) each subunit of hemoglobin has identical oxygen-binding sites.
D) all subunits of a hemoglobin molecule must have the same conformation at any given time.
E) each oxygen-binding site of hemoglobin is on a separate subunit.