Accepted Answer
The answer is variant D because 'Trout are fish' Is a simple sentence and 'are fish' exprime a quality of the subject, so the verb 'are fish' meets the rules of the predicate nominative.
The answer is variant D because 'Trout are fish' Is a simple sentence and 'are fish' exprime a quality of the subject, so the verb 'are fish' meets the rules of the predicate nominative.