Final answer:
If Hershey and Chase had found only 35S in bacterial cells, the conclusion would be that proteins are the genetic material, but actual results showed 32P inside the cells, confirming DNA as genetic material.
Step-by-step explanation:
If Hershey and Chase had found only 35S in their bacterial cells, it would imply that the material they labeled with 35S was the genetic material. Since 35S was used to label proteins, this outcome would suggest that proteins are the genetic material. However, in their actual experiments, only 32P, which labels DNA, was found inside the bacterial cells, confirming that DNA is the genetic material, not proteins. Therefore, the correct conclusion if only 35S was found would be that proteins are the genetic material (C).