Assertion: Synonyms are the most important of all rules of ICBN.
Reason: Out of the two or more scientific names given to the organism, the oldest name is recognized as valid name and other names as synonyms

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 but R is false.
D. If both A and R are false

Answer

**Step-by-Step Solution:**

1. **Understand the Assertion and Reason**: The assertion states that synonyms are the most important of all rules of ICBN (International Code for Botanical Nomenclature). The reason explains that when multiple scientific names exist for an organism, the oldest name is considered valid, while the others are deemed synonyms.

2. **Define ICBN**: The ICBN is a set of rules and recommendations dealing with the naming of plants. It ensures that each species has a unique and universally accepted scientific name.

3. **Explain the Concept of Synonyms**: In botanical nomenclature, when a species is named more than once (often due to separate discoveries), the oldest name takes precedence. The newer names are classified as synonyms.

4. **Provide an Example**: For instance, if a plant species is discovered in India in 1960 and named "X," and then the same species is discovered in China in 1980 and named "Y," according to ICBN, "X" is the valid name, and "Y" is a synonym.

5. **Evaluate the Assertion and Reason**: Both the assertion and the reason are true. The reason correctly explains why synonyms are important in the context of ICBN, as it clarifies which name should be used when multiple names exist.

6. **Conclusion**: Therefore, both the assertion and reason are true, and the reason is the correct explanation of the assertion.

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