A force $\bar{F}=k\left(y^{2} \hat{i}+x \hat{j}\right)$, where $k$ is a positive constant, acts on a particle when it is at position $(x, y)$. First, the particle is taken through path $\mathrm{OAB}$ and the work done by the force is $\mathrm{W}_{\mathrm{OAB}^{*}}$. Then the particle is taken on through path $\mathrm{OCB}$ and the work done by the force is $\mathrm{W}_{\mathrm{ocB}^{\prime}}$. Then
(a) $\mathrm{W}_{\text {OAB }}=\mathrm{ka}^{2}$
(b) $\mathrm{W}_{\mathrm{OCB}}=\mathrm{ka}^{2}$
(c) the force is conservative
(d) the force is non-conservative