The correct answer is C. Gideon was the son of a tribal medicine men, so all of this knowledge was passed onto him. However, he (along with the other African servants) do not reveal the name of the medicinal root, regardless of (and perhaps in spite of) the potential monetary benefits involved with telling the white people about their medicine.
The answer you are looking for here is C.
C because the thesis statement explains what the entire essay is about.
The introductory information addresses what the study will entail(talk about)
The setting discusses existing data on your topic and where it takes place
