[单选题]
A force moves an object in the direction of the fonya+xb e2.c)n9cz if ;ryr2 h;rce. Thex/ cu5s(cb sx;4 kd.qk graph in Fig. 6-1 shows the force versus the object's position. Find the work done when c(.kxx5;dsu k cs4/qbthe object moves from 0 to 6.0 m.
A. $20 \; J$
B. $40 \; J$
C. $60 \; J$
D. $80 \; J$
