Support for this answer choice?

I selected the answer choice "German shepards can function both as police dogs and seeing eye dogs"... I didn't think this answer choice was clearly supported either because it uses the word "both" when it should be "either" given the example. But, I didn't see how any of the other statements were supported any better by the stimulus

That's what the passage is trying to convince us of. This is a synthesis of the first two sentences, that pit bull is not a breed of dog, but it is more like occupation-designating terms such as police dog.

While not common, it does occasionally happen that the conclusion is split up between two sentences as is the case here.