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

Options

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

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the most common substrate used in distilleries for the production of ethanol. A substrate is a substance on which an organism grows or is attached.

2. **Identifying the Options**: The options provided are:
- A) Corn meal
- B) Soya meal
- C) Ground gram
- D) Molasses

3. **Analyzing Each Option**:
- **Corn Meal**: While corn is used in some ethanol production, it is not the most common substrate in distilleries.
- **Soya Meal**: This is primarily used for animal feed and not commonly used for ethanol production.
- **Ground Gram**: Similar to soya meal, ground gram is not typically used in distilleries for ethanol.
- **Molasses**: This is a by-product of sugar production and is widely used in distilleries for ethanol production due to its high sugar content.

4. **Conclusion**: Based on the analysis, the most common substrate used in distilleries for the production of ethanol is **molasses**.

5. **Final Answer**: The correct answer is **D) Molasses**.