The relationship between force and position is shown in Fig. $4.19$ (in one-dimensional case). The work done by the force in displacing a body from $x=1 \mathrm{~cm}$ to $x=$ $5 \mathrm{~cm}$ is
(A) 20 ergs
(B) $60 \mathrm{ergs}$
(C) 70 ergs
(D) 700 ergs