Answer:
The correct answer is most likely benign tumor
Step-by-step explanation:
By elimination:
Oncogenes are genes, not a mass of cells, so this cannot be the correct answer.
Carcinogens are cancer causing agents, so again, not a mass of cells.
A malignant tumor is a tumor that can spread to other tissues, and is therefore not normal cells.
Benign tumor is the only remaining choice :).