Assertion. `t`-Butyl Methyl ether is not prepared by the reaction of `t-`butyl bromide with sodium methoxide.
Reason: Sodium methoxide is a strong nucleophile.

Options

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

Explanation

To solve the question regarding the assertion and reason about `t`-Butyl Methyl ether and sodium methoxide, we can break it down into clear steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
The assertion states that `t`-Butyl Methyl ether is not prepared by the reaction of `t`-butyl bromide with sodium methoxide.

2. **Analyzing the Reactants**:
- `t`-butyl bromide (C4H9Br) is a tertiary alkyl halide.
- Sodium methoxide (CH3O^-Na^+) is a strong base and a strong nucleophile.

3. **Reaction Mechanism**:
When `t`-butyl bromide reacts with sodium methoxide, one might expect an ether formation through nucleophilic substitution. However, because sodium methoxide is a strong base, it is more likely to act as a base rather than a nucleophile.

4. **Base vs Nucleophile**:
- Strong bases tend to abstract protons (H+) rather than participate in substitution reactions.
- In this case, sodium methoxide will abstract a proton from the `t`-butyl bromide, leading to the formation of an alkene through a beta elimination reaction (E2 mechanism).

5. **Conclusion on Assertion**:
Since the reaction leads to the formation of an alkene instead of an ether, the assertion is indeed true.

6. **Understanding the Reason**:
The reason states that sodium methoxide is a strong nucleophile. While this is true, it does not explain why `t`-Butyl Methyl ether is not formed in this reaction. The strong nucleophilicity of sodium methoxide is overshadowed by its strong basicity, which drives the elimination reaction instead.

7. **Conclusion on Reason**:
The reason is true, but it does not correctly explain the assertion. Therefore, while both the assertion and reason are true, the reason is not a correct explanation for the assertion.

### Final Answer:
The correct option is that both the assertion and reason are true, but the reason is not the correct explanation for the assertion.