Gerard, it looks like you are just trying to do what a lot of people do with multi guess questions. Find the answer and select it without understanding the subject.
In your ice query, the answer is in the question, read it. There two types of airframe icing, rime and clear. As the ice described is cloudy and brittle, it isn't clear. Answers b and c are red herrings.
Mixed ice is sometimes mentioned but that is just what is sounds like, a bit of each.