The construction of first rDNA was done using plasmid of :

The correct answer is Option (3) → Salmonella typhimurium

Option (3) Salmonella typhimurium — Correct. An antibiotic resistance gene was linked to the native plasmid of Salmonella typhimurium.

NCERT Extract:
Principles of Biotechnology – “… Let us now focus on the first instance of the construction of an artificial recombinant DNA molecule. The construction of the first recombinant DNA emerged from the possibility of linking a gene encoding antibiotic resistance with a native plasmid (autonomously replicating circular extra-chromosomal DNA) of Salmonella typhimurium. Stanley Cohen and Herbert Boyer accomplished this in 1972 by isolating the antibiotic resistance gene by cutting out a piece of DNA from a plasmid which was responsible for conferring antibiotic resistance.”