The correct answer is option B, that is, a neighborhood there had been built over a toxic dump.
In 1978, Love Canal, situated close to the Niagara Falls in the upstate New York, was a nice small working-class enclave with many houses and a school. It just occurred to have been sitting at the top of 21000 tons of toxic industrial waste, which had been buried underground in the 1940s and 50s by a local company.
The families living in the chemicals were not familiar that they were being encountered with poisonous chemicals, nor were they aware of the chemical wastes being dumped into the soil, rivers, and air. The toxic wastes influenced the lives and damaged the environment.