The First Experiments That Demonstrated Protective Adaptive Immune Responses to Tumors

The first experiments that demonstrated protective adaptive immune responses to tumors involved transplantation of chemical carcinogen-induced tumors between rodents.Which of the following facts was learned from these experiments?

A) There are only a limited number of antigens that can evoke a protective anti-tumor response.
B) Transplanted sarcomas can evoke protective cytolytic T lymphocyte responses.
C) Carcinomas express tumor antigens that are recognized by T lymphocytes.
D) Protective immune responses against tumors are largely mediated by antibodies.
E) Spontaneously arising tumors are often eradicated by cytolytic T lymphocytes.