[单选题]
A 4.00-kg box of fruit slides 8.0 m down a rc u 1f+:mm8qctamp, inclined atm 8mi4mab-lib ms +)4ku0 m(yw fw9a,y $30^{\circ}$ from the horizontal. If the box slides at a constant velocity of 5.00 m/s, what is the work done by the weight of the box?
A. $157 \; J$
B. $-157 \; J + 78.4 \; J$
C. $78.4 \; J$
D. $-78.4 \; J$
