Which are appropriate for a writer to include in a conclusion? check all that apply. (a) a compelling quotation (b) a thought-provoking question (c) an idea that supports the thesis (d) a speculation about future research (e) an explanation of information from sources

Okay, so (a) doesn't seem right because as a general rule of thumb you should always keep your quotations in the body and out of the conclusion.
(b) doesn't seem right either, because although it depends on the type of essay, questions shouldn't be asked in essays; instead they should be explained. I'm leaning more towards (c), because in the conclusion you should always wrap up your essay by restating the thesis. (d) might be a second choice, because its common to speculate about what will happen in the future as it relates to your topic. (e) doesn't seem right to me because you should have already explained your information in the body paragraphs. Hope this helps!