Hi aaba,
Another great question! Let's go through the answers, one problem at a time, and narrow things down to (hopefully) one correct answer!
The main differences between each answer seem to be pronoun-related. Let's look at two common problems with pronouns: pronoun-antecedent agreement and vague pronouns. By doing this, we should be able to narrow down our answers quickly.
A. to their new customers all the costs, including taxes, that
they will be expected to pay.
Answer A is
INCORRECT because the pronoun "they" is too vague - it's not clear if "they" is referring to the cable companies or the customers.
B. to their new customers all the costs, including taxes, that the customers will be expected to pay.
This is
CORRECT because the pronoun "their" is plural and agrees with its plural antecedent "cable companies." It also doesn't have any unclear or vague pronouns at the end, making it very clear who will be paying.
C. to
its new customers all the costs, including taxes, that
they will have to pay.
Answer C is
INCORRECT because it uses the singular pronoun "its" to refer to the plural "cable companies." It also uses the vague pronoun "they," which means it's unclear if the cable companies or the customers are paying the costs.
D. to the companies' new customers all the costs, including taxes, that
the companies have paid.
Answer D is
INCORRECT because it changes the meaning of the original sentence. It ends by saying that cable companies will report the costs the cable companies paid, NOT what the customers will be paying.
E. to their new customers all the costs, including taxes, that
its customers will be expected to pay.
Answer E is
INCORRECT because it uses the singular pronoun "its" to refer back to the plural "cable companies."