$(10$ points$)$ A $90\mathrm{.}0-kg$ skydiver with an open parachute falls straight downward through a vertical height of $300$ m $.$ The skydiver's velocity remains constant. What is the work done by the gravitational force? $g=9\mathrm{.}8\frac{m}{s^2}.$

A$.-2\mathrm{.}65{10}^{5}J$

B$.0$ J

C$.+2\mathrm{.}65{10}^{5}J$

D$.-2\mathrm{.}21{10}^{5}J$