A variable force acts on a 2.0 -kilogram mass, displacing the mass 5.0 meters. The force and displacement are graphed above. Determine the work done on the mass by the variable force.
(A) 5 $\mathrm{J}$
(B) 10 $\mathrm{J}$
(C) 15 $\mathrm{J}$
(D) 20 $\mathrm{J}$
(E) 30 $\mathrm{J}$