[A]: Monocot stem has collateral open vascu- lar bundle.
[R]: Open vascular bundle is without cam- bium.

Options

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

Answer

To analyze the statements provided in the question, we will break down the assertion and the reason step by step.

### Step 1: Understanding the Assertion
The assertion states that "Monocot stem has collateral open vascular bundle."
- In monocots, the vascular bundles are arranged in a specific way. They are typically scattered throughout the stem and are classified as closed vascular bundles. This means that they do not have cambium tissue between the xylem and phloem. Therefore, the assertion is **false**.

### Step 2: Understanding the Reason
The reason states that "Open vascular bundle is without cambium."
- Open vascular bundles are characterized by the presence of cambium tissue between the xylem and phloem. This allows for secondary growth. Therefore, the statement that "open vascular bundle is without cambium" is also **false**.

### Step 3: Conclusion
Both the assertion and the reason are false. Thus, the correct answer is that both A and R are false.

### Final Answer
Both the assertion (A) and the reason (R) are false.

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