Replication is the process of producing two new (deoxyribose nucleic acid) molecules from a single parental. In the given data, the prenatal DNA and nucleotides are not radioactively labeled. However, nucleotide is radiolabeled.
The adjoined picture below shows the replication of the parental with given nucleotides:
Thus, only one daughter molecule will be radioactive.
The adjoined picture below shows the replication of the second parental with given nucleotides:
Thus, only both daughter molecules will be radioactive.