Plasmid of which bacterium was first time used in recombinant DNA technology?

Correct option is B. Salmonella typhimurium
The word 'plasmid' was first coined by Joshua Lederberg in 1952. He used it to describe 'any extrachromosomal hereditary element'.
Lederberg first used the term in a paper he published describing some experiments he and his graduate student Norton Zinder conducted on Salmonella bacteria and its virus P22. During the course of this work, they observed that virus particles could somehow pick up bacterial genes and transfer them to another host, a process they called transduction.
By the 1960s a number of plasmids had been identified. This included fertility plasmids first observed, which carry the fertility genes necessary for bacterial conjugation. Another group were resistance (R) plasmids which carry the genes that encode resistance to antibiotics or poisons. It was an R plasmid (pSC101) that proved instrumental to the generation of the first recombinant DNA molecule.
Hence, Plasmid of a bacterium, Salmonella typhimurium was first time used in recombinant DNA technology.
So, the correct answer is 'Salmonella typhimurium'.