Deoxyribonucleotide triphosphate serves the dual purpose of ___A_____ and ___B_____ in the process of replication of DNA.

Deoxyribonucleoside triphosphates serve dual purposes. In addition to acting as substrates, they provide energy for polymerisation reaction (the two terminal phosphates in a deoxynucleoside triphosphates are high-energy phosphates, same as in case of ATP).