Which of the following is NOT a cause that led to the disaster at Bhopal in 1984a.improper setting of alarm clockb.non-functioning of refrigeration unit and flare towerc.pouring of water into the MIC tankd.technical incompetence of plant engineer

The option that is NOT a cause that led to the disaster at Bhopal in 1984 is "improper setting of alarm clock".

Here's why:

a. Improper setting of alarm clock: This is not a cause of the disaster. The disaster was not caused by an alarm clock setting, but by a series of technical and safety failures.

b. Non-functioning of refrigeration unit and flare tower: This is a cause of the disaster. The refrigeration unit, which was designed to cool the MIC (Methyl Isocyanate) tank and prevent it from overheating, was not functioning properly. The flare tower, which was supposed to burn off any escaping MIC, was also not working.

c. Pouring of water into the MIC tank: This is a cause of the disaster. Water entered the MIC tank, causing a chemical reaction that led to the release of a large amount of toxic gas.

d. Technical incompetence of plant engineer: This is a cause of the disaster. The plant was not maintained properly, and safety procedures were not followed, leading to the disaster.