Which of the following reactions is/are feasible?

Options

A. `CH_(3)CH_(2)Br+overset(+)NaO^(-)-overset(CH_(3))overset("| ")underset(CH_(3))underset("| ")"C "-CH_(3) rarr CH_(3)CH_(2)O-overset(CH_(3))overset("| ")underset(CH_(3))underset("| ")"C "-CH_(3)`
B. `CH_(3)-overset(CH_(3))overset("| ")underset(CH_(3))underset("| ")"C "-Cl+Na^(+)O^(-)CH_(2)CH_(3)rarrCH_(3)CH_(2)-O-overset(CH_(3))overset("| ")underset(CH_(3))underset("| ")"C "-CH_(3)`
C. Both a and b
D. None of the above

Explanation

To determine the feasibility of the given reactions, we need to analyze each reaction based on the SN2 mechanism and the concept of steric hindrance.

### Step-by-Step Solution:

1. **Identify the Reactions**:
- The first reaction involves CH3CH2Br (ethyl bromide) reacting with NaO-C(CH3)3 (tert-butoxide).
- The second reaction involves a tertiary alkyl halide.

2. **Understand the SN2 Mechanism**:
- In an SN2 reaction, a nucleophile attacks an electrophile (alkyl halide), leading to the displacement of a leaving group (halide ion).
- The reaction proceeds in a single step, and the rate depends on the concentration of both the nucleophile and the substrate.

3. **Evaluate Steric Hindrance**:
- **First Reaction**:
- The alkyl halide (ethyl bromide) is a primary halide, which means it has minimal steric hindrance.
- The nucleophile (tert-butoxide) can easily approach and attack the carbon atom, leading to the formation of the ether product.
- Therefore, this reaction is feasible.

- **Second Reaction**:
- The alkyl halide is tertiary, meaning it has three alkyl groups attached to the carbon atom.
- The steric hindrance is significant, making it difficult for the nucleophile to attack the carbon atom.
- Instead of an SN2 reaction, an elimination reaction occurs, leading to the formation of an alkene as the major product.
- Hence, this reaction is not feasible for the formation of an ether.

4. **Conclusion**:
- The first reaction is feasible, while the second reaction is not feasible for ether formation.

### Final Answer:
- The correct answer is that only the first reaction (Option A) is feasible.