Which of the following are not used as food preservatives?

Sodium hydrogen-carbonate is not used as a food preservative that is option (ii) because it’s an anticaking agent used to prevent the formation of lumps.

Now let us revise where the other preservatives can be used

(i) Table salt is used to preserve pickles

(ii) Cane sugar can be used as preservative to make jam and jellies

(iii) Benzoic acid can preserve sweets, ice cream etc.

Hence, according to question option(ii) is correct rest options (i), (iii) and (iv) are incorrect.