The variety of coal used as old house coal is

Options

A. anthracite
B. peat
C. lignite
D. bituminous

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the type of coal that is commonly used in old houses.

2. **Identifying Coal Varieties**: There are several types of coal, including:
- Anthracite
- Bituminous
- Sub-bituminous
- Lignite

3. **Analyzing Bituminous Coal**:
- Bituminous coal is known for its soft texture and is often referred to as "black coal."
- It contains a tar-like substance called bitumen.

4. **Comparing Coal Types**:
- Bituminous coal is of higher quality compared to lignite and sub-bituminous coal.
- It has low ash content when burned, making it more efficient and cleaner for household use.

5. **Conclusion**: Given its properties and common use, the variety of coal used as old house coal is **Bituminous coal**.

### Final Answer:
The variety of coal used as old house coal is **Bituminous coal**.

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