Answer: DNA polymerases require a primer to initiate DNA synthesis. The enzyme primase catalyzes the synthesis of the primers from which DNA polymerases can begin synthesis. Primers are short oligonucleotides, ranging from 6 to 60 nucleotides long. They can be made of ribonucleotides or a mixture of deoxyribonucleotides and ribonucleotides. The principal primase in E. coli is the 60 kDa protein called DnaG protein, the product of the dnaG gene. The major primase in eukaryotic cells is DNA polymerase α.
Therefore, the molecule that serves as the primer for DNA polymerases during DNA replication is C. A short RNA molecule.