The most common substance used in distilleries for the production of ethanol is:

Options

A. Molasses
B. Corn meal
C. Soyabean
D. Ground gram

Answer

To solve the question regarding the most common substance used in distilleries for the production of ethanol, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the most common substance used in distilleries for ethanol production. Ethanol is typically produced through fermentation.

2. **Identify the Fermentation Process**: Ethanol production involves the fermentation process, which is primarily carried out by yeast. The yeast used in this process is often Saccharomyces cerevisiae.

3. **Consider the Options**: The options provided are:
- Option 1: Molasses
- Option 2: Cornmeal
- Option 3: Soybean
- Option 4: Ground graham

4. **Evaluate Each Option**:
- **Molasses**: A byproduct of sugar production, rich in sugars, and commonly used in fermentation processes for ethanol production.
- **Cornmeal**: While it can be used for ethanol production, it is less common than molasses.
- **Soybean**: Primarily used for oil extraction and animal feed, not typically for ethanol production.
- **Ground Graham**: Not a common substrate for ethanol production.

5. **Conclusion**: Based on the evaluation, molasses is the most common substance used in distilleries for ethanol production due to its high sugar content and suitability for fermentation by yeast.

6. **Final Answer**: The correct option is **Option 1: Molasses**.