The word that is opposite in meaning to the word 'muddled' is—

'Muddled' means confused, disorganized, or jumbled. Its opposite is something clear, organized, or systematic. 'Ordered' means arranged in a clear, systematic way, which is the direct antonym of muddled. 'Confused', 'chaotic', and 'rumpled' are all synonyms of muddled, not antonyms. Hence (3) ordered is correct.