You will be given a definition of a task first, then some input of the task.
In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").

Fact1: Antigens are found on cancer cells and the cells of transplanted organs., Fact2: Examples of animal organs are kidneys and hearts., Question: antigens are found on cancer cells and the cells of transplanted what? (A) h2o (B) kidneys (C) genetics (D) operation (E) lungs (F) the skin (G) epidermal (H) alveoli
Output:
B