`Xunderset((ii)H_3O^(o+))overset((i)KMnO_4//H_2O // Delta)toHOOC-oversetoverset(O)(||)C-CH_2-CH_2-CH_2-CH_2-COOH`
X may be

Options

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B.
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D.

Explanation

To solve the question, we need to determine the compound X that, when treated with potassium permanganate (KMnO4) in the presence of water and heat, leads to the formation of a specific dicarboxylic acid.

### Step-by-Step Solution:

1. **Identify the Product**: The product given is a dicarboxylic acid with the structure HOOC-CO-CH2-CH2-CH2-CH2-COOH. This indicates that there are two carboxylic acid groups (-COOH) at the ends of a carbon chain.

2. **Understand the Reagents**: The reagent used is potassium permanganate (KMnO4), which is a strong oxidizing agent. It can oxidize alkenes to form diols and further oxidize them to carboxylic acids.

3. **Determine the Structure of X**: Since KMnO4 will oxidize an alkene, we need to consider that X must be a compound that can yield the dicarboxylic acid upon oxidation. The presence of two -COOH groups suggests that X should be a compound with a double bond that can be cleaved to form these groups.

4. **Consider Possible Structures for X**:
- A reasonable candidate for X is a compound that has a double bond between two carbon atoms, with sufficient carbon atoms on either side to allow for the formation of the dicarboxylic acid.
- A suitable structure could be a compound like 1,5-hexadiene, which has a double bond between the first and second carbon atoms.

5. **Oxidation Mechanism**: When 1,5-hexadiene is treated with KMnO4:
- The double bond will be oxidized to form a glycol (diol).
- Further oxidation will cleave the carbon-carbon bond, leading to the formation of two carboxylic acid groups at the ends of the carbon chain.

6. **Final Structure Confirmation**: After the oxidation and hydrolysis, the resulting structure matches the dicarboxylic acid given in the question.

7. **Conclusion**: Therefore, the compound X is likely to be 1,5-hexadiene or a similar alkene that can yield the specified dicarboxylic acid upon oxidation with KMnO4.