The line y=1 is a horizontal line paralel to the x axis. This means that a reflection about it can't change the value of the x coordinate:
[tex]A_x=3=A^{\prime}_x[/tex]
Regarding the y coordinate, in A we have that:
[tex]\begin{gathered} A_y=-2 \\ y-A_y=1-(-2)=3 \end{gathered}[/tex]
Since A' is the reflection of A about line y=1 then we have that:
[tex]\begin{gathered} y-A^{\prime}_y=-(y-A^{}_y))=-3 \\ y-A^{\prime}_y=1-A^{\prime}_y=-3 \\ A^{\prime}_y=1+3=4 \end{gathered}[/tex]
Then the coordinates of point A' are (3,4) and the correct answer is the second one.
