Assertion : Order of a reaction with respect to any reactant can be zero, positive negative of fractional.
Reason : Rate of a reaction cannot decrease with increase in concentration of a reactant or a product.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

To solve the question, we need to analyze the assertion and the reason provided separately.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the order of a reaction with respect to any reactant can be zero, positive, negative, or fractional.
- **Explanation**: The order of a reaction is defined as the exponent of the concentration term in the rate law expression. It can take various values based on experimental observations. For example:
- Zero order: The rate does not depend on the concentration of the reactant.
- Positive order: The rate increases with an increase in the concentration of the reactant.
- Negative order: The rate decreases with an increase in the concentration of the reactant.
- Fractional order: The order can be a fraction, indicating a more complex relationship.

2. **Understanding the Reason**:
- The reason states that the rate of a reaction cannot decrease with an increase in the concentration of a reactant or a product.
- **Explanation**: This statement is incorrect. In some reactions, particularly those with negative order, the rate can decrease as the concentration of a reactant increases. For example, if the reaction follows a rate law where the concentration of a reactant is raised to a negative power, an increase in that concentration will lead to a decrease in the rate of reaction.

3. **Conclusion**:
- Since the assertion is true (the order can indeed be zero, positive, negative, or fractional), but the reason is false (the rate can decrease with an increase in concentration for negative orders), we conclude that the correct option is:
- **Assertion is true, but Reason is false.**

### Final Answer:
- The assertion is true, and the reason is false.