eliminating virulence genes would be the correct answer
Explanation:
The correct answer was that since if the relationship between viruses and oncogenes is modified, the release of the oncoprotein is avoided, as well as the presence of malignant neoplasms before viral infections such as: epstein barr virus and kaposi's sarcoma.
So my answer is that the virulence factors of a virus cannot be modified to make viral vectors safer, the viral vector would be human and this is safer if its protoncogenes do not become oncogenes due to viral infections.