DNA replication always proceeds in only one direction because the ________ of the incoming nucleotide is attached to the free ________ of the growing DNA strand.
A) 5ʹ-phosphate / 3ʹ-hydroxyl B) 3ʹ-phosphate / 5ʹ-hydroxyl C) 5ʹ-deoxyribose / 3ʹ-base D) 3ʹ-base / 5ʹ-deoxyribose