Assertion : cis -2- butene gives meso-2, 3-butanediol with dilute
alkaline `KMnO_(4)` solution.
Reason : Dilute alkaline `KMnO_(4)` solution gives trans addition with alkenes.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that cis-2-butene gives meso-2,3-butanediol when treated with dilute alkaline KMnO4.
- **Cis-2-butene Structure**: The structure of cis-2-butene can be represented as:
```
H3C H
\ /
C=C
/ \
H3C H
```
- When cis-2-butene undergoes oxidation with dilute alkaline KMnO4 (which is a syn-dihydroxylation reaction), it adds hydroxyl groups (OH) across the double bond.

2. **Reaction with Dilute Alkaline KMnO4**:
- The reaction will yield:
```
H3C OH
\ /
C=C
/ \
OH H3C
```
- The product formed is 2,3-butanediol, and since it has a plane of symmetry, it is classified as a meso compound.

3. **Conclusion on Assertion**:
- The assertion is **True** because cis-2-butene indeed gives meso-2,3-butanediol when treated with dilute alkaline KMnO4.

4. **Understanding the Reason**:
- The reason states that dilute alkaline KMnO4 gives trans addition with alkenes.
- However, this is incorrect because dilute alkaline KMnO4 actually leads to syn addition (cis addition) of hydroxyl groups across the double bond.

5. **Conclusion on Reason**:
- The reason is **False** because it incorrectly describes the type of addition that occurs with dilute alkaline KMnO4.

### Final Answer:
- Assertion: True
- Reason: False