[A]: Antitranspirants are used to retard tran- spiration.
[R]: AbA and PMA are not antitranspirants

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 given statements regarding antitranspirants, we can break down the solution into the following steps:

### Step 1: Understand the Assertion
The assertion states that "Antitranspirants are used to retard transpiration."
- Antitranspirants are indeed substances that are applied to plant leaves to reduce water loss through transpiration. They help in conserving water in plants, especially during dry conditions.

### Step 2: Evaluate the Reason
The reason states that "AbA and PMA are not antitranspirants."
- AbA (Abscisic Acid) and PMA (Phenyl Mercuric Acetate) are both substances that can influence transpiration. PMA is known to be an antitranspirant because it induces stomatal closure, which reduces transpiration.

### Step 3: Determine the Truth of Each Statement
- The assertion is true because antitranspirants do help in reducing transpiration.
- The reason is false because PMA is indeed an antitranspirant, contrary to what the reason states.

### Step 4: Conclusion
Based on the evaluation:
- The assertion is true, and the reason is false. Therefore, the correct option is that the assertion is true, and the reason is false.

### Final Answer
The correct option is: **If assertion is true, reason is false.**

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