Hey there!
The word reflected means when something is basically coping everything that you do. So, for example, when I look in a mirror, the mirror would reflect everything that I would do.
So, from looking at the graph above, as we should
remember the
![\left[\begin{array}{ccc}\boxed{x-axis}\end{array}\right]](https://img.qammunity.org/2019/formulas/mathematics/high-school/4o9a4jedao28p4rim6x7d6g2i9u97gnwtd.png)
is the

that is
(horizontal) and the

is the

that is
(vertical).
So, from knowing this information of graphs, we now know that
![\left[\begin{array}{ccc}AB\end{array}\right]](https://img.qammunity.org/2019/formulas/mathematics/high-school/on3rtey59pclfqex9ylpkpsfc5nqsrnexx.png)
are reflecting over the

which is the line that is
(horizontal).
Your correct answer would be
. . .

Hope this helps you!
~Jurgen