Which of following pairs does not represent resonance sturctures?

Options

A. `CH_(3)-C-=overset(o+)N-overset(Ɵ)O and CH_(3)-overset(o+)C=N-overset(Ɵ)O`
B.
C. `CH_(2)=overset(o+)N=overset(Ɵ)N and overset(Ɵ)CH_(2)-overset(o+)N-=N`
D.

Explanation

To determine which pair does not represent resonance structures, we need to analyze the given pairs of structures. Resonance structures are different ways of drawing the same molecule that differ only in the placement of electrons, not the arrangement of atoms.

### Step-by-Step Solution:

1. **Identify the Given Pairs**:
We need to look at the pairs of structures provided in the question. Let's denote them as Pair A, Pair B, Pair C, and Pair D.

2. **Analyze Pair A**:
- Check if the structures can be interconverted by moving electrons (lone pairs or bonds).
- If you can move a lone pair to form a double bond or move a double bond to form a lone pair, then these structures are resonance structures.

3. **Analyze Pair B**:
- Repeat the same process as in Pair A.
- Look for the possibility of electron movement without changing the position of atoms.

4. **Analyze Pair C**:
- Again, check if the structures can be interconverted by moving electrons.
- If they can be interconverted, they are resonance structures.

5. **Analyze Pair D**:
- In this case, check if one of the structures involves a change in the number of atoms or the formation of a new bond that cannot be achieved by simple electron movement.
- If one structure involves a proton transfer (like NH3 losing an H+ ion), then this pair does not represent resonance structures.

6. **Conclusion**:
- After analyzing all pairs, identify which pair does not fit the criteria of resonance structures.
- Based on the analysis, Pair D is the correct answer because it involves a proton transfer, indicating that it is not a simple resonance structure.

### Final Answer:
The pair that does not represent resonance structures is Pair D.