Answer:
Reflective
Step-by-step explanation:
The radiation pressure of the wave that totally absorbed is given by;
![P_(abs)= (I)/(C)](https://img.qammunity.org/2022/formulas/physics/college/exkpbozucqsjxumbeyr1q5p6jj8ec8c5zc.png)
and While the radiation pressure of the wave totally reflected is given by;
![P_(ref)= (2I)/(C)](https://img.qammunity.org/2022/formulas/physics/college/nopmsir57wo6uvcepukbwvqkhl2x26tu03.png)
Now compare the two-equation you can clearly see that the pressure due to reflection is larger than absorption therefore the sail should be reflective.