Well...this kind of question is...not sure how to say it but...answers may vary from different people. But I would go with A. Unusual
Because B? Dangerous? Yeah Mars is dangerous but saying it’s red doesn’t mean it’s dangerous. Saying Mars have dust storms would mean it’s dangerous. C. Different? That’s what I meant when I say answers may vary. Some people would choose this because earth is not red, and therefore, different. But I believe unusual is the best word here. D. Beautiful? Yeah that’s more like an opinion, no. E. Similar? Similar in what way? Earth isn’t red.