Which of the following dihalides are `alpha- omega`, gem and vicinal dihalides?
1,2-Dichlorobutane

Explanation

To determine the type of dihalide that 1,2-dichlorobutane is, we need to analyze its structure and understand the definitions of the different types of dihalides: alpha-omega, geminal, and vicinal.

### Step-by-Step Solution:

1. **Identify the Structure of 1,2-Dichlorobutane**:
- Butane has a four-carbon chain. The structure of 1,2-dichlorobutane can be represented as:
\[
\text{CH}_3\text{CH}(\text{Cl})\text{CH}(\text{Cl})\text{CH}_3
...