15.

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

Item C: as Klussmann came to be known is a parenthesis, placed between the subject and the predicate of the sentence, separated by double commas, item C is correct.

A/B items: Brackets are equivalent to double commas here, so commas are not needed if there are brackets, and A/B items have extra commas.