Answer:
D) My brother—who is a superb actor—will audition tomorrow for a film role.
Step-by-step explanation:
Non restrictive clauses are those unnecessary words or groups of words/ clauses that does not add any value or meaning to the sentence. They can also be omitted for they serve no use in the sentence. It adds an extra information about the sentence but which have no significance.
With a non restrictive clause in the sentence, the use of a comma before and after the clause is mandatory. But since the options provided gives no such option, the best rewritten with the use of the em dash.
Thus, the final correctly punctuated sentence will be
My brother—who is a superb actor—will audition tomorrow for a film role.