Respuesta :
B. a cat's
since it started out with "a dog's need" it is talking about one dog. so it would be talking about the companionship of one cat, so it would be "a cat's"
since it started out with "a dog's need" it is talking about one dog. so it would be talking about the companionship of one cat, so it would be "a cat's"
'b' is correct because when you say a cat's ,companionship is understood and doesn't need to be repeated