Cohen and Boyer created the first recombinant DNA using plasmid of :

Salmonella typhimurium

The correct answer is Option (3) - Salmonella typhimurium

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.This recombinant DNA was then transferred into Escherichia coli.

Thermus aquaticus is a thermostable bacterium whose enzymes are used in PCR.
Bacillus thuringiensisis is used to make Bt cotton (pest-resistant crop).