ANSWER
a reflection of the point across the line y = -x
Step-by-step explanation
We have the cordinates of the point (m, 0) and m is not equal to zero.
Let us check each of the options:
=> a reflection of the point across the x axis causes the y cordinate to become its negative but the x cordinate remains the same.
So it would transform (m, 0) to (m, 0)
=> a reflection of the point across the y-axis causes the x cordinate to become its negative but the y cordinate remains the same.
So it would transform (m, 0) to (-m, 0)
=> a reflection of the point across the line y = x causes the x and y cordinates to change places.
So it would transform (m, 0) to (0, m).
=> a reflection of the point across the line y=-x causes the x and y cordinates to change places and be negated.
So it would transform (m, 0) to (0, -m)
So, option D is the answer.