One mole crystal of a metal halide of the type MX with molecular weight $$119 \text{ g}$$ having face centered cubic structure with unit cell length $$6.58 \mathring{\text{A}}$$ was recrystallized. The density of the recrystallized crystal was found to be $$2.44 \text{ g cm}^{-3}$$. The type of defect introduced during the recrystalization is

A

additional $$\text{M}^+$$ and $$\text{X}^-$$ ions at interstitial sites

B

Schottky defect

C

F-centre

D

Frenkel defect