Each of the 4 choices has been drawn step by step as follows:
the first transformation is drawn in light grey
the second transformation is drawn in dark grey
the third transformation is described as how it should be.
Choice I, picture I: 
Rotate 180°, reflect over the x-axis, reflect over the line y=x
the last transformation should be : reflect with respect to the y-axis
Choice II, picture II: 
Reflect over the x-axis, rotate 180°, reflect over the x-axis
the last transformation should be : reflect with respect to the y-axis
Choice III, picture III: 
Rotate 180°, reflect over the y-axis, reflect over the line y=x
the last transformation should be : reflect with respect to the x-axis
Choice IV, picture IV: 
Reflect over the y-axis, reflect over the x-axis, rotate 180°
the last transformation should be : rotate 180° CORRECT!
Answer:  Reflect over the y-axis, reflect over the x-axis, rotate 180°