A tumour including plasmid widely used in the production of transgenic plants is that of

The correct option is D Agrobacterium tumefaciens.
Agrobacterium tumefaciens is the causative agent of crown gall disease, a form of tumor and is a gram-negative, rod-shaped bacteria.
The symptoms of the disease are caused by the insertion of a small segment of DNA (known as the T-DNA, for 'transfer DNA'), from a plasmid, into the plant cell, which is incorporated at a semi-random location into the plant genome. This site can be used for the insertion of the desired gene into the plant genome, after making the plasmid non-pathogenic.