Under physiological conditions, the protein hemerythrin exists as an octamer of eight chains of the kind shown

Question:

Under physiological conditions, the protein hemerythrin exists as an octamer of eight chains of the kind shown in Problem 3.
a. Name two symmetries possible for this molecule.
b. Which do you think is more likely? Explain.
c. For the more likely symmetry, what kinds of interactions (isologous, heterologous, or both) would you expect? Why?