[单选题]
A force moves an object in the direc:m;(auw) a p.awx2uknl wmz8:j)1f9hnk )pz ftion of the force. The graph in Fig. 6-y886; wyxnf s p(;ufoj1 shows the force versus the object's p6;of; sxnw f8y8yup(josition. Find the work done when the object moves from 2.0 to 4.0 m.
A. $20 \; J$
B. $40 \; J$
C. $60 \; J$
D. $80 \; J$
