The cost of safely disposing of the toxic chemicals is approximately five times what the company paid to purchase it.(Option D)
<h3>What is sentence correction?</h3>
Sentence correction or sentence improvement is a type of grammatical practice where a sentence is given with a word or a phrase that requires grammatical changes or improvement.
Now,
Here, we are talking about "toxic chemicals", that is "plural" but in the Part D of the sentence, "it" refers to the singular chemical.
Hence, the correction needs to be made at Option D; the correction would be: "paid to purchase them."