The correct option is (a) 0=\(\int_{V_e}\)(σijδεij+ρüiδui)dV-\(\int_{V_e}\)fiδuidV-∮se\(\hat{t_i}\)δuids

The best explanation: The vector form of the principle of virtual displacements applied to plane finite elastic element with volume, Ve and surface, se is 0=\(\int_{V_e}\)(σijδεij+ρüiδui)dV-\(\int_{V_e}\)fiδuidV-∮se\(\hat{t_i}\) δuids, where “δ” denotes the variational operator, (σij and εij are the components of stress and strain tensors, respectively, and fi and ti are the components of the body force and boundary stress vectors, respectively.