Answer: C) She says that some pets at the shelter were abandoned by their owners.
Explanation: In the given passage we can see the explanation of why most pets in shelters are there not because of them, in fact, most of them are very gentle, sociable, sweet and fearlessly affectionate, but they end up in shelters often because they are abandoned by their owners (who move, have a change in their family situation, don't want a pet any longer, etc). So the correct answer is option C.