Option A is incorrect. Agrobacterium tumefaciens is primarily used to deliver genes of interest into eukaryotic host cells, specifically plant cells, and not typically into prokaryotic cells. It is known for its ability to naturally genetically engineer plants by inserting a portion of its 'Ti' (tumor-inducing) plasmid, the 'T-DNA', into the plant cell DNA. This makes it a useful tool for plant genetic engineering. However, its utility in transferring genes to prokaryotic host cells is quite limited.