A scientist carried out an experiment to follow the movement of carbon atoms within animal cells. To do this, the scientist added glucose with radioactively labeled carbon atoms to a culture of cells growing in a Petri dish. After a certain amount of time had passed, the scientist tested parts of cells for radioactivity. Radioactivity was detected in various biomolecules, including DNA.

Which of the following statements best explains why radioactivity was detected in the DNA?
Choose 1

(Choice A)
The DNA was in close proximity to the radioactive glucose during its formation.

(Choice B)
Carbon atoms that were once in the radioactively labeled glucose were used to form DNA.

(Choice C)
The DNA was made up of radioactively labeled glucose subunits.