`CH_(3)-O-underset(O)underset(||)(C )-CH_(2)-COOH`
The correct IUPAC name of the above compound is :

Options

A. 2-Acetoxy ethanoic acid
B. 2-Methoxycarbonyl ethanoic acid
C. 3-Methoxyformyl ethanoic acid
D. 2-Methoxyformyl acetic acid

Answer

To determine the correct IUPAC name of the compound `CH₃-O- (C=O)-CH₂-COOH`, we will follow the steps of IUPAC nomenclature systematically.

### Step-by-Step Solution:

1. **Identify the Functional Groups**:
- The compound contains a carboxylic acid group (-COOH) and an ether (methoxy group -O-CH₃). The carbonyl group (C=O) is also present.

2. **Determine the Longest Carbon Chain**:
- The longest carbon chain will include the carboxylic acid as it has a higher priority. The longest chain here consists of 2 carbons (from the carboxylic acid) and one carbon from the carbonyl group.

3. **Number the Carbon Chain**:
- Start numbering from the end closest to the carboxylic acid group. The numbering will be as follows:
- 1: COOH (carboxylic acid)
- 2: C=O (carbonyl)
- 3: O-CH₃ (methoxy)

4. **Identify Substituents and Their Positions**:
- The methoxy group (-O-CH₃) is attached to the second carbon in the chain.

5. **Combine the Names**:
- The substituent (methoxy) is named first, followed by the main chain name. The main chain is a carbonyl compound (carbonyl) followed by the carboxylic acid (ethanoic acid).
- Therefore, the name will be structured as:
- 2-methoxy (for the methoxy group at position 2)
- carbonyl (for the carbonyl group)
- ethanoic acid (for the carboxylic acid).

6. **Final IUPAC Name**:
- Putting it all together, the correct IUPAC name of the compound is **2-methoxycarbonyl ethanoic acid**.

### Final Answer:
The correct IUPAC name of the compound is **2-methoxycarbonyl ethanoic acid**.