Correct Lewis structure is:

Options

A. `[:underset(..)overset(..)O-C=underset(..)overset(..)N:]^(-)`
B. `[C=C:]^(2-)`
C. `[:underset(..)overset(..)Cl-underset(..)overset(..)O:]^(-)`
D. `:overset(..)N=overset(..)O:`

Explanation

To determine which of the given molecules has the correct Lewis structure, we will analyze each option step by step, focusing on the octet rule.

### Step 1: Analyze the first option
1. **Count the number of atoms**: Identify the number of oxygen and carbon atoms.
- There are 2 carbon atoms and 8 oxygen atoms.

2. **Count the electrons**: For each bond, remember that one bond counts as 2 electrons.
- Count the total number of electrons around each atom.
- For carbon, if it has fewer than 8 electrons, it does not satisfy the octet rule.

3. **Conclusion**: If carbon does not have a complete octet, this structure is incorrect.

### Step 2: Analyze the second option
1. **Count the electrons around carbon**:
- In this structure, carbon is doubly bonded.
- Count the electrons: 4 electrons for the double bond.

2. **Check the octet rule**:
- If carbon has fewer than 8 electrons, it does not satisfy the octet rule.

3. **Conclusion**: This structure is also incorrect if carbon does not meet the octet rule.

### Step 3: Analyze the third option
1. **Count the electrons for Cl and O**:
- Count the electrons around chlorine and oxygen.
- For chlorine, if it has 8 electrons (2 from the bond with oxygen and 6 as lone pairs), it satisfies the octet rule.
- For oxygen, count the total electrons (2 from the bond with chlorine and 6 as lone pairs).

2. **Conclusion**: If both Cl and O have complete octets, this structure is correct.

### Step 4: Analyze the fourth option
1. **Count the electrons around nitrogen and oxygen**:
- Count the electrons for nitrogen and oxygen.
- If nitrogen has 8 electrons (including bonds and lone pairs), it satisfies the octet rule.
- For oxygen, count the total electrons.

2. **Check for the correct bonding**:
- Nitrogen and oxygen typically form a triple bond with one lone pair on nitrogen.
- If the structure shows one bond less than expected, it is incorrect.

3. **Conclusion**: If nitrogen and oxygen do not have the expected bonding, this structure is incorrect.

### Final Conclusion
After analyzing all options, the correct Lewis structure is the one where both chlorine and oxygen satisfy the octet rule, which is option C.

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