The answer would be complex sentence, because it consists of an individual clause (The explorers brightened the dark cave) and a dependent clause (when they lit a torch from their cooking fire).
Edward III of England created the first English dukedom by naming his eldest son Edward, the Black Prince, as Duke of Cornwall in 1337, after he lost his own title of Duke of Normandy.
I think the answer is C)Herbs can provide positive medicinal effect if used properly.
C is the best answer because
Herbs don't have curing power, they can help you feel better, but they don't have curing powers. This is why A is not the best answer.
Herbs may be plants filled vitamins and minerals but that is not that does not really support the author's viewpoint regarding the value of herbal healers.
So C would be the best choice. Herbs can provide positive medicinal effects if used properly, and this goes along with the authors views of herbal healers.