All the following statements about Stanley Cohen and Herbert Boyer are correct but one is wrong. Which one is wrong?

They discovered recombinant DNA (r-DNA) technology and this marks the birth of modern biotechnology

They first produced, healthy sheep clone, a Finn Dorset lamb, Dolly, from the differentiated adult mammary cells

They invented genetic engineering by combining a piece of foreign DNA containing a gene from a bacterium with a bacterial plasmid using the enzyme restriction endonuclease

They isolated the antibiotic resistance gene by cutting out a piece of DNA from a plasmid which was responsible for conferring antibiotic resistance