Match List-I with List-II
List-I                                             List-II
(A)    negatively charged sol           (I)    Fe$$_2$$O$$_3$$ · xH$$_2$$O
(B)    macromolecular colloid        (II)    CdS sol
(C)    positively charged sol           (III)   Starch
(D)    Cheese                                    (IV)   a gel
Choose the correct answer from the options given below

We need to match each item in List-I with the correct item in List-II based on properties of colloids.

CdS sol is a well-known example of a negatively charged sol. Other examples include As$$_2$$S$_3$$ sol and gold sol. So (A) negatively charged sol → (II) CdS sol.

Starch is a macromolecular colloid — it is a naturally occurring polymer that forms colloidal solutions in water. So (B) macromolecular colloid → (III) Starch.

Fe$$_2$$O$$_3$$ · xH$$_2$$O (ferric oxide hydrosol) is a positively charged sol. Other examples include Al(OH)$$_3$$ sol. So (C) positively charged sol → (I) Fe$$_2$$O$$_3$$ · xH$$_2$$O.

Cheese is a well-known example of a gel (solid dispersed in liquid medium that has a semi-solid structure). So (D) Cheese → (IV) a gel.

The correct matching is: (A)-(II), (B)-(III), (C)-(I), (D)-(IV).

Hence, the correct answer is Option C.