`C_(3)H_(6)overset(NBS) to A overset("HBr/Peroxide")to B overset("Na/ether") to C Aoverset(KCN) D---`

Explanation

To convert the compound \( C_3H_6 \) to the final product \( C \) through the specified reactions, we will follow these steps:

### Step 1: React \( C_3H_6 \) with NBS
- **Reaction**: \( C_3H_6 + NBS \rightarrow A \)
- **Explanation**: The compound \( C_3H_6 \) is likely propene. When propene reacts with N-bromosuccinimide (NBS), it undergoes a bromination reaction. This reaction typically occurs at the allylic position, leading to the formation of a brominated product. The product \( A \) will be 3-bromopropene.

### Step 2: React \( A \) with HBr in the presence of Peroxide
- **Reaction**: \( A + HBr \overset{Peroxide}{\rightarrow} B \)
...