Which choice shows the coordinates of b’ if the trapezoid is reflected across the x-axis?

For this case we have that the original point is given by:
 B = (7, 2)
 As the point is reflected through the x axis, then we have the following transformation:
 (x, y) > (x, -y) > (x ', y')
 Applying the transformation to the original ordered pair we have:
 (7, 2) > (7, - (2)) > (7, -2)
 
 Point B 'is given by:
 B '= (7, -2)