To radioactively label a cell's DNA, it is cultured in a solution containing radioactive nucleotides.

In order to ensure that any new DNA strands it produces are not radioactive, it is taken out of the radioactive solution and cultivated in a regular medium. The cell replicates its DNA and divides in the usual media. The two daughter cells divide and duplicate their DNA to create a total of four daughter cells. Which of the following illustrates the DNA of the four cells if a dotted line represents a radioactive DNA strand and a solid line indicates a nonradioactive DNA strand?