[deleted because problem is from a banned source - see below]
Ron, Stacy,
I selected the right option but I want to get a concept clarified.
A introduces pronoun ambiguity I believe, which is why C is a better choice. But if you read the sentence, "them" cannot refer to anything except the telephone companies. One would be very tempted to select this, also because it's a shorter and more direct version of C. Can you tell me what's really wrong with this option?