A)is generated by copying genomic DNA with the polymerase chain reaction and cloning the resulting complementary DNA (cDNA). B)is generated by copying messenger RNA (mRNA)with the enzyme reverse transcriptase and cloning the resulting complementary DNA (cDNA). C)corresponds to the protein complement of a cell. D)doesn't contain introns. E)doesn't contain introns because it is generated by copying messenger RNA (mRNA)with the enzyme reverse transcriptase and cloning the resulting complementary DNA (cDNA).