In genetic engineering, rDNA defines
DNA with a piece of foreign DNA
DNA with a piece of RNA
DNA which takes part in recombination
DNA not associated with recombination
As we have already studied in Biotechnology & Its Principles -
Recombinant DNA, which is often shortened to rDNA, is an artificially made DNA strand that is formed by the combination of two or more gene sequences. Hence, the correct option is (a).