Concept:The word "occasional" means happening from time to time. Its correct spelling has two 'c's and one 's'.Explanation:Option A "Occasional" is correctly spelled: O-c-c-a-s-i-o-n-a-l.Option B "Occational" is wrong because it is missing the first 's'.Option C "Occassional" is wrong because it has a double 's' instead of a single 's'.Option D "Occasionale" is wrong because it adds an extra 'e' at the end.Thus, only option A matches the standard English spelling.Answer:Option A. Occasional