When Diagnosed with Hemolytic Disease of the Newborn (HDN),why Does

When diagnosed with hemolytic disease of the newborn (HDN) ,why does the newborn develop hyperbilirubinemia after birth but not in utero?

A) Excretion of unconjugated bilirubin through the placenta into the mother's circulation is no longer possible.
B) Hemoglobin does not break down into bilirubin in the intrauterine environment.
C) The liver of the fetus is too immature to conjugate bilirubin from a lipid-soluble to water-soluble form.
D) The destruction of erythrocytes producing bilirubin is greater after birth.