The correct answer is A. aikatau. The word "dafa" in the sentence is a verb (aikatau), specifically a cooking verb meaning "to cook" or "to prepare". In the sentence, "dafa" is describing the action of cooking, which is a verb. The other options - bayanau (adverb), sifa (adjective), suna (noun), and wakilin suna (pronoun) - do not fit the context of the word "dafa" in the sentence. Therefore, the correct answer is A. aikatau.