Assertio (A): Order of the reaction can be zero or fractional.
Reason (R): We cannot determine order from balanced chemical equation.

Options

A. Both A and R are true and R is the correct explanation for A
B. Both A and R are true but R is NOT the correct explanation of A
C. A is true but R is false
D. A is false and R is true

Explanation

To analyze the assertion and reason provided in the question, we will break down the concepts of reaction order and how it relates to the balanced chemical equation.

### Step-by-Step Solution:

1. **Understanding Reaction Order**:
- The order of a reaction refers to the power to which the concentration of a reactant is raised in the rate law expression.
- It can be zero, positive, fractional, or even negative. For example, if the rate of a reaction is independent of the concentration of reactants, it is a zero-order reaction.

2. **Assertion (A)**:
- The assertion states that the order of the reaction can be zero or fractional. This is indeed true.
- Zero-order reactions have a rate that does not depend on the concentration of the reactants, while fractional order reactions occur in complex reactions where the rate depends on the concentration raised to a fractional power.

3. **Reason (R)**:
- The reason states that we cannot determine the order from the balanced chemical equation. This is also true.
- The stoichiometry of the balanced equation does not provide information about the rate of reaction or the order. The order must be determined experimentally.

4. **Conclusion**:
- Both the assertion and the reason are true. However, the reason provided does not correctly explain the assertion. The assertion is about the possible values of order, while the reason discusses the method of determining it.
- Therefore, the correct answer is that both the assertion and reason are true, but the reason is not the correct explanation of the assertion.

### Final Answer:
- Assertion (A) is true: The order of the reaction can be zero or fractional.
- Reason (R) is true: We cannot determine order from the balanced chemical equation.
- The reason does not correctly explain the assertion.