Frenkel Defect is a stoichiometric defect, which are point defects in crystal structure which do not affect the stoichiometry of the solid. Stoichiometric defects show vacancy as well as intrinsic defects. Frenkel Defect is shown by ionic solids, where the smaller ion (usually cation) is dislocated from its normal site to an interstitial site. It creates a vacancy defect at its original site and an interstitial defect at its new location. Frenkel defect is also called dislocation defect and it does not change the density of the solids.

Thus, the correct option is (i) and (ii).