For a Virus to Reproduce, It Must Insert Its DNA

For a virus to reproduce, it must insert its DNA into the host cell's genome. How might this cause cancer in the host?

A) The viral DNA could insert a gene that controls cell division into the host's DNA.
B) Because the host cell is much smaller than the virus, the host cell must expand until it becomes a tumor large enough to hold the virus.
C) The virus could turn off an oncogene.
D) Viruses cannot cause cancer.