Which is most likely the result of genetic engineering?

Genetic engineering is the process of manually adding new DNA or genetic material to an organism. The latest example of genetic engineering is immunotherapy. Healthy white blood cells are genetically modified to target a specific type of cancer. These modified cells are then injected into a person with this specific type of cancer. These cells then target the cancer cells and destroy them. This immunotherapy is more advanced than Chemotherapy as it only targets the rogue cells, not all the cells.