Correct Option: B

The Ti plasmid contains most of the genes required for tumor formation. Wounded plants exude phenolic compounds that stimulate the expression of the virulence genes(vir -genes), which are also located on the Ti plasmid. The vir genes encode a set of proteins responsible for the excision, transfer and integration of the T-DNA into the plant genome. The genes in the T-DNA region are responsible for the tumorigenic process.