A.isClass B.isKindOfClass C.isMemberOfClass D.conformsToProtocol
A.setName(@"obj") B.name=@"object" C.self.name=@"object";
A.AVAudioSessionCategoryAmbient B.AVAudioSessionCategorySoloAmbient C.AVAudioSessionCategoryPlayback D.AVAudioSessionCategoryPlayAndRecord