Never, just by the definition of scalene triangle and regular polygon. A scalene triangle has three different angles, and a regular polygon is a polygon who's angles are all congruent. Therefore, a scalene triangle is never a regular polygon.
The correct answer among the choices listed is option C. A scalene triangle is never a regular polygon. From the definition of the terms, we can say that the answer is never. A scalene triangle has three different angles while a regular polygon is has angles that are all congruent.
