Q: Fact 1: Antigens are found on cancer cells and the cells of transplanted organs. Fact 2: Antigens are proteins foreign to the body. Given the two facts above, proteins foreign to the body can be found where?

Possible answers:
[a]. in the lymph nodes
[b]. in nerve cells
[c]. in the kidneys
[d]. on cancer cells
[e]. critical organs
[f]. mouth of rivers
[g]. Earth orbiting the Sun
[h]. the skin
The answer is:
[d].