Genetic recombination by transduction in bacteria was discovered first in this

Question

$\begin {array} {1 1} (1)\;Salmonella\: typlimurium & \quad (2)\;Escherichia\: coli \\ (3)\;Streptococcus\: pneumoniae & \quad (4)\;Agrobacterium\: tumefaciens \end {array}$