Fetal haemoglobin, also known as HbF is the main oxygen transport protein in the human fetus during the last seven months of development in the uterus and persists in the newborn until roughly 6 months old. It is able to bind oxygen with greater affinity than the adult form, giving the developing fetus better access to oxygen from the mother's bloodstream. It has 2 alpha and 2 gamma chains. Hence, option b is correct.

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