Match the matching is
`{:(,"Set-I",,"Set-II"),((A),"Teargas",(1),[C_(2)H_(4)Cl]_(2)S),((B),"Mustured gas",(2),COCl_(2)),((C),"Phosgene",(3),C Cl_(3)NO_(2)),((D),"Teflon",(4),(C_(2)F_(4))_(n)):}`
Correct the matching is

Options

A. `{:(,A,B,C,D),((1),3,1,2,4):}`
B. `{:(,A,B,C,D),((2),1,2,4,3):}`
C. `{:(,A,B,C,D),((3),2,3,4,1):}`
D. `{:(,A,B,C,D),((4),4,2,1,3):}`

Explanation

To solve the matching question, we will go through each compound in Set-I and identify its corresponding formula from Set-II.

### Step-by-Step Solution:

1. **Identify Tear Gas:**
- Tear gas is known to be **Chloropicrin**.
- The chemical formula for Tear Gas is **CCl3NO2**.
- Therefore, we match **Tear Gas (A)** with **(3) CCl3NO2**.

2. **Identify Mustard Gas:**
- Mustard gas is not actually a gas; it is an oily liquid.
- The chemical formula for Mustard Gas is **C4H8Cl2S**.
- However, in the provided options, the closest match is **(1) C2H4Cl** which is incorrect. The correct formula should be **C4H8Cl2S** but for the sake of matching, we will consider it as **(1)**.

3. **Identify Phosgene:**
- Phosgene is a toxic gas.
- The chemical formula for Phosgene is **COCl2**.
- Therefore, we match **Phosgene (C)** with **(2) COCl2**.

4. **Identify Teflon:**
- Teflon is a polymer made from **C2F4**.
- The chemical formula for Teflon is represented as **(C2F4)n**.
- Therefore, we match **Teflon (D)** with **(4) (C2F4)n**.

### Final Matching:
- A → 3 (Tear Gas → CCl3NO2)
- B → 1 (Mustard Gas → C4H8Cl2S, but we will match it with C2H4Cl for this question)
- C → 2 (Phosgene → COCl2)
- D → 4 (Teflon → (C2F4)n)

### Conclusion:
The correct matching is:
- A → 3
- B → 1
- C → 2
- D → 4

Thus, the final answer for the matching is **3124**.