Answer:
A reflection does not change lengths, so answers B and D are not right.
In most cases, a reflection will change the position of any object; so answer A would be right.
However, if segment AB is contained inline l, its reflection in line l will be in the same position.
Or if line l is the perpendicular bisector of segment AB, then the reflection of segment AB inline l will be in the same position as segment AB, but with the two endpoints, A and B switched.
So, with the question as posed and no further information about the relationship of line l and segment AB, the best answer is A; but in certain cases answer, C could be right.