Explanation:

- The Bhopal Gas Tragedy was a catastrophic industrial accident that occurred at the Union Carbide pesticide plant in Bhopal, India.

- It released approximately 40 tons of methyl isocyanate gas, affecting thousands of people.

- The incident is one of the world's worst industrial disasters, with long-lasting health and environmental effects.

- Option 1: 1986 - This is two years after the Bhopal disaster actually happened.

- Option 2: 1982 - This is before the gas tragedy occurred.

- Option 3: 1984 - This is the year when the tragedy took place, specifically on December 2-3.

- Option 4: 1980 - This is four years prior to the disaster.