The correct option is C DNA segments having radioactive isotopes
A probe is a single-stranded sequence of DNA or RNA used to search for its complementary sequence in a sample genome. The probe is placed in contact with the sample under conditions that allow the probe sequence to hybridize with its complementary sequence. The probe is labelled with a radioactive or chemical tag that allows its binding to be visualized which is similar to the way labelled antibodies are used to probe a sample for the presence of a specific protein.