C. Gideon’s position as a tribal medicine man dictates that he not betray the secret to outsiders.
In the passage it states that "[T]hey all realized he would never give in." This best shows that Gideon will not reveal the medicine he used. This means that any answer which shows he did give away the medicine information is incorrect. Options C and D are eliminated. Option A can also be eliminated because it only encourages kindness to the scientist, it does not say anything about his actions with the medicinal plant.