Answer:
b. for fear of blowing the large cloud of gas to another city
Explanation:
Firstly, before the explosion of the Union Carbide plant, the flare tower had been out of service. Secondly, the flare tower was incapable of bringing the concentration of large amount of gas down to a safe level. It could barely handle a quarter of the leaked gas. All these factors made the operators scared of turning the flare tower on as it will only blow out the cloud of gas to another city.
