Final answer:
In Hershey and Chase's experiments, γ32P-ATP was used to label DNA, demonstrating that DNA is the genetic material. This is because the γ-phosphate group of ATP is the one that gets incorporated into DNA during replication or transcription.
Step-by-step explanation:
The researchers in Hershey and Chase's experiments used γ32P-ATP to label DNA. ATP, or adenosine triphosphate, has three phosphate groups, α, β, and γ. When labeling nucleic acids such as DNA, the γ-phosphate group is typically radiolabeled because this is the group that is incorporated into the DNA strand during the formation of the phosphodiester bond.
In their classic experiment, Hershey and Chase used the radioactive isotopes 32P to label DNA and 35S to label the protein coat of bacteriophages. It was observed that bacteria infected with phages containing 32P-labeled DNA produced new phages with radioactivity present, indicating that only the DNA entered the bacterial cells and thus demonstrating that DNA is the genetic material.
Given that the phosphate group attached at the 5' end of the DNA during phosphodiester bond formation is the γ-phosphate of the nucleotide triphosphate, we can deduce that the correct choice for the type of 32P labeled ATP used is γ32P-ATP (Option C).