Personally, i think the topic should have several angles and for it to be specific
Answer: The US government’s skillful use of research and intelligence enabled a vital spy mission.
The correct answer among all the other choices is c. had to be transferred onto light-sensitive paper, and then inverted. Using traditional photographic paper, a slide, which is printed as a positive image, had to be transferred onto light-sensitive paper, and then inverted. Thank you for posting your question. I hope that this answer helped you. Let me know if you need more help.