I believe the answer might be D. Hope this helps!!! Sorry if it doesn't!
Answer: C.Although extracting natural gas from shale in a process called fracking is believed to be safe by industry experts, scientists beg to differ with them.
Explanation: A conclusion is the last part of something, its end or result. In a written work, the conclusion is used to introduce some final comments at the end of the piece of writing. From the given options, the claim restatement that would be most appropriate to start the conclusion paragraph, is the corresponding to option C, because it summarizes the main idea or claim of the essay, without developing more information.