Concept:A synonym is a word that has the same or nearly the same meaning as another word. "Reckless" means acting without care or thought.Explanation:"Reckless" describes someone who takes unnecessary risks without considering consequences."Rash" also means acting too quickly without careful thought.Thus, "Rash" is the closest synonym among the options."Prudent," "Cautious," and "Careful" all mean the opposite – showing care and thought.Hence, the correct choice is D. Rash.Answer:D. Rash