Match List-I with List - II :
`{:("List - I","List - II"),("(A) negatively charged sol","(I) "Fe_2O_3.xH_2O),("(B) macromolecular colloid","(II) CdS sol"),("(C) positively charged sol","(III) Starch"),("(D) Cheese","(IV) a gel"):}`

Options

A. (A) - (II), (B) - (III), (C) - (IV), (D) - (I)
B. (A) - (II), (B) - (1), (C) - (III), (D) - (IV)
C. (A) - (II), (B) - (III), (C) - (I), (D) - (IV)
D. (A) - (I), (B) - (III), (9) - (II), (D) - (IV)

Explanation

To match List-I with List-II, we will analyze each item in List-I and find the corresponding item in List-II based on the characteristics of colloids.

### Step-by-Step Solution:

1. **Identify negatively charged sol (List-I A)**:
- A negatively charged sol is one where the dispersed particles carry a negative charge. A common example of a negatively charged sol is **CdS sol** (cadmium sulfide).
- **Match**: (A) negatively charged sol → (II) CdS sol

2. **Identify macromolecular colloid (List-I B)**:
- A macromolecular colloid consists of large molecules (macromolecules) that can form colloidal solutions. A well-known example of a macromolecular colloid is **starch**.
- **Match**: (B) macromolecular colloid → (III) Starch

3. **Identify positively charged sol (List-I C)**:
- A positively charged sol is one where the dispersed particles carry a positive charge. An example of a positively charged sol is **Fe₂O₃.xH₂O** (iron(III) oxide hydrate).
- **Match**: (C) positively charged sol → (I) Fe₂O₃.xH₂O

4. **Identify cheese (List-I D)**:
- Cheese is a colloidal system that can be classified as a gel. It is a semi-solid mixture that retains moisture and has a gel-like structure.
- **Match**: (D) Cheese → (IV) a gel

### Final Matching:
- (A) negatively charged sol → (II) CdS sol
- (B) macromolecular colloid → (III) Starch
- (C) positively charged sol → (I) Fe₂O₃.xH₂O
- (D) Cheese → (IV) a gel

### Answer:
The correct matches are:
- A - II
- B - III
- C - I
- D - IV