Scenario Jim Has Become Particularly Interested in the Genetic Basis of of Cancer

Scenario
Jim has become particularly interested in the genetic basis of cancer and has spent considerable time reading published papers about oncogenes. He learned that as early as 1972 researchers suggested that mutations in proto-oncogenes caused by carcinogens can convert the proto-oncogenes to oncogenes. He asked you to answer a couple of questions about this because he did not have a sufficient biology background.
-Jim learned that some cancer cells produce more growth factors than others. Which explanation most likely explains this observation?

A) Tumor suppressor genes may have been activated in the cells with more growth factors.
B) Mutations in homeotic genes may have occurred in the cells with fewer growth factors.
C) Vitamin C and Vitamin E may have been deficient in the cells with more growth factors.
D) Proto-oncogenes may have mutated to become oncogenes in the cells with more growth factors.