The international treaty of Montreal protocol become effective in the year of

Options

A. 1989
B. 1999
C. 1889
D. 1987

Answer

To solve the question regarding the year the Montreal Protocol became effective, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: The Montreal Protocol is an international treaty aimed at protecting the ozone layer by phasing out the production of numerous substances responsible for ozone depletion.

2. **Identify Key Dates**:
- The Montreal Protocol was signed in 1987.
- The question specifically asks when it became effective.

3. **Determine the Effective Year**:
- The Montreal Protocol officially became effective in 1989. This means that while it was signed in 1987, the regulations and commitments outlined in the treaty were implemented starting in 1989.

4. **Select the Correct Answer**:
- Among the options provided (1989, 1999, 1889, 1987), the year when the Montreal Protocol became effective is 1989.

### Final Answer:
The Montreal Protocol became effective in the year **1989**.

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