There are a number of so-called "high affinity" mutations in hemoglobin that may cause an elevated red blood cell count and a ruddy complexion. These may be associated with:

I. disruption of a hydrogen bond that stabilizes the T conformation
II. disruption of a hydrogen bond that stabilizes the R conformation
III. gain of oxygen binding capacity per hemoglobin tetramer
IV. loss of oxygen binding capacity per hemoglobin tetramer
V. decreased formation of salt bridges involving the C-termini of the alpha and beta chains when the protein is deoxygenated.

a. I, llI
b. II, III
c. III, IV, V
d. I, II, V
e. I, V
f. II, IV, V