A : Montreal protocol suggested the reduction of ODS.
R : A land mark international agreement taken in Earth summit held at Rio de Janeiro.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are ture but the reason is not the correct explanation of the assertion, then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements, then mark (4).

Answer

To solve the assertion and reason question regarding the Montreal Protocol and the Earth Summit, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Assertion**: The assertion states that "Montreal Protocol suggested the reduction of ODS (Ozone Depleting Substances)."
- **Analysis**: The Montreal Protocol, established in 1987, is indeed an international treaty aimed at reducing the production and consumption of substances that deplete the ozone layer, such as chlorofluorocarbons (CFCs). Therefore, the assertion is **true**.

2. **Identify the Reason**: The reason states that "A landmark international agreement was taken in the Earth Summit held at Rio de Janeiro."
- **Analysis**: The Earth Summit, held in 1992, was indeed a significant conference addressing global environmental issues. However, it is important to note that the Montreal Protocol was not a result of this summit; it was established earlier in 1987. Thus, while the Earth Summit was an important event, it is not directly related to the Montreal Protocol. Therefore, the reason is **false**.

3. **Conclusion**: Since the assertion is true and the reason is false, we conclude that the assertion stands independently without the support of the reason.

### Final Answer:
- Assertion: True
- Reason: False