Correct option is C. about three times
Depression in freezing point is a colligative property. In case of $$MgCl_2$$ value of van't Hoff factor will be more. No. of ions yielded when a molecule of $$MgCl_2$$ gets dissociated in its aqueous solution is 3. Thus one molecule of 0.01 M $$MgCl_2$$ gives out three particles/ions in solution, thereby increasing the number of particles present in its solution to three times. It is because of this that depression in freezing point 0.01 M $$MgCl_2$$ will be three times as compared to that of 0.01 M glucose solution, where no dissociation of the molecule takes place.