Ishow you the question and the paragraph so tell me the answer and tell me why is it thosei will give you 25 points

I believe it is D because like in the quotation there was uncertainty of what would happen

Because the sentence is talking about how we didn't know radium would help humans survive stuffs like cancer, D is the right answer. D talks about how radium wasn't originally discovered as something that would prove useful in hospitals - they had no idea they'd use it to help cure people.