The incorrect IUPAC name is

Options

A. `{:(" "O),(" ||"),(CH_(3)-C-CH-CH_(3):" 2-Methyl-3-butanone"),(" |"),(" "CH_(3)):}`
B. `{:(CH_(3)-CH-CH-CH_(3):" 2, 3-Dimethylpentane"),(" |"" |"),(" "CH_(3)" "CH_(2)-CH_(3)):}`
C. `CH_(3)-C equiv C-CH (CH_(3))_(2)`: 4-Methylpent-2-yne
D. `{:(CH_(3)-CH-CH-CH_(3):" 2-Bromo-3-chlorobutane."),(" |"" |"),(" "Cl" "Br):}`

Explanation

To determine the incorrect IUPAC name from the given options, we will follow a systematic approach to analyze each name based on the rules of IUPAC nomenclature.

### Step-by-Step Solution:

1. **Identify the Longest Carbon Chain**:
- For each compound, identify the longest continuous chain of carbon atoms. This is crucial as the longest chain determines the base name of the compound.

2. **Number the Carbon Chain**:
- Number the carbon atoms in the chain starting from the end nearest to the highest priority functional group (like a carbonyl group, double bond, or triple bond). This ensures that the substituents receive the lowest possible numbers.

3. **Identify and Name Substituents**:
- Identify any substituents attached to the main carbon chain. Each substituent should be named and its position on the chain indicated by the carbon number it is attached to.

4. **Combine the Names**:
- Combine the names of the substituents and the base name of the compound. The substituents should be listed in alphabetical order, regardless of their position numbers.

5. **Check for Correctness**:
- Compare the constructed IUPAC name with the provided options to identify which one is incorrect.

### Application of Steps:

1. **Option 1**:
- Longest chain: 4 carbons (butane).
- Numbering: Start from the end nearest to the carbonyl (C=O).
- Substituent: 2-methyl.
- Correct name: 2-methyl-2-butanone.
- This name is correct.

2. **Option 2**:
- Longest chain: 5 carbons (pentane).
- Numbering: Start from the end nearest to the substituents.
- Substituents: 2,3-dimethyl.
- Correct name: 2,3-dimethylpentane.
- This name is correct.

3. **Option 3**:
- Longest chain: 5 carbons with a double bond (pent-2-yne).
- Numbering: Start from the end nearest to the triple bond.
- Substituent: 4-methyl.
- Correct name: 4-methyl-1-pentene.
- This name is correct.

4. **Option 4**:
- Longest chain: 4 carbons (butane).
- Numbering: Start from the end nearest to the substituents.
- Substituents: Bromo at position 2 and Chloro at position 3.
- Correct name: 2-bromochloro-butane.
- This name is correct.

### Conclusion:
After analyzing all options, the incorrect IUPAC name is the first one: **2-methyl-2-butanone**.