Complete the reaction :
`B overset(MnO_(2),H^(+))to C_(6)H_(5)CH_(3) underset("Heat")overset(KmnO_(4),H^(+))to A`

Explanation

To complete the reaction given in the question, we will follow these steps:

### Step 1: Identify the starting material (B)
The starting material (B) is a compound that will undergo oxidation in the presence of MnO2 and H+. Based on the information provided, we know that the product of this reaction is C6H5CH3 (toluene).

### Step 2: Determine the structure of B
Since we are starting with toluene (C6H5CH3) and we are using MnO2, which is a mild oxidizing agent, we can deduce that B must be a compound that can be oxidized to form toluene. The most likely candidate is benzyl alcohol (C6H5CH2OH).

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