Complete the following reactions sequence:
`CH_(3)-overset(O)overset(||)(C)-CH_(3) underset((ii)H_(2)O)overset((i)CH_(3)MgBr)to(A) underset(Ether)overset(Na" metal")to(B) overset(CH_(3)-Br)to(C)`

Explanation

To complete the given reaction sequence, we will follow the steps outlined in the video transcript. Here’s the detailed step-by-step solution:

### Step 1: Reaction of Acetone with Methyl Magnesium Bromide
1. **Starting Material**: The starting material is acetone (CH₃COCH₃).
2. **Reagent**: We add methyl magnesium bromide (CH₃MgBr), which is a Grignard reagent.
3. **Mechanism**: The nucleophilic carbon from the Grignard reagent (CH₃⁻) attacks the electrophilic carbon of the carbonyl group in acetone.
4. **Product Formation**: This results in the formation of a tertiary alcohol intermediate:
- **Intermediate A**: (CH₃)₂C(OH)CH₃ (tert-butyl alcohol).
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