This is a run on sentence because a run on sentence has no word to join them together!
Result , outcome, effect, aftermath and aftereffect.
Answer: Capture your key points and comment on their significance
Explanation:
Since the person is working on your conclusion, but you're having trouble challenging your readers, the strategies that will help you with that is to capture the key points and comment on their significance.
By capturing the key points, the important aspect of the story will be highlighted and their significance will be commented on. Therefore, the correct option is A.