Originally Posted by Capuchin
you know that if a ray of light is perpendicular to a surface, it doesnt experience refraction (because it is travelling along the normal), so yes you are correct.
However the question is ambiguous, a ray can still travel through the center of the lens but be incident from a different angle, in this case the result would be different as the ray is not travelling along the normal.
However, I think your teacher wanted you to think about the case where it is travelling along the normal, and "it doesnt bend" is the correct answer in that case. Well done! :)