Answer:
C). It should restate it in as much detail as possible.
C). what they have learned from your essay
Step-by-step explanation:
The Conclusion is the last paragraph of an essay and as an author, one would like to briefly reiterate the key ideas discussed in the essay as it reminds the reader of the strength of the key argument and supporting evidence to justify it. Thus, the conclusion must 'restate the ideas of the topic paragraph' as it will connect the essay coherently, remind the readers of the main arguments and evidence, and offer a sense of closure.
The key idea behind adding a conclusion to the essay is to convey an 'overall essence, message, or lesson that the readers learned by the end.' It nudges them about the solution of the author's purpose(as discussed at the beginning of the work) by telling them how the ideas given in the thesis statement were successfully delivered to them with sufficient evidence.