Assertion : Stomata generally open in light and close in dark.
Reason : Transpiration is enhanced by heating effect of light.

Answer

To solve the assertion-reason question, we will analyze both the assertion and the reason step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Stomata generally open in light and close in dark."
- This is true because during the day, when photosynthesis occurs, plants need to take in carbon dioxide and release oxygen. Stomata facilitate this gas exchange. In the absence of light (at night), photosynthesis does not occur, and to conserve water, stomata close.

2. **Understanding the Reason**:
- The reason states that "Transpiration is enhanced by the heating effect of light."
- This statement is also true. Light increases the temperature, which can enhance the rate of transpiration. Higher temperatures can increase the evaporation of water from the plant's surface, leading to increased water loss.

3. **Analyzing the Relationship**:
- While both the assertion and reason are correct, the reason does not directly explain the assertion. The opening and closing of stomata in response to light is primarily related to photosynthesis and water conservation, while the increase in transpiration due to light is a separate phenomenon.

4. **Conclusion**:
- Therefore, both statements are correct, but the reason does not explain the assertion. The correct answer is that both statements are true, but the reason is not a valid explanation for the assertion.

### Final Answer:
- **Option B**: Both statements are correct, but the reason statement is not explaining the assertion.