The addition of which of the following sentences would create an effective paragraph? Dogs and cats are both fantastic pets. Dogs are loving and playful. Cats are clean and self-sufficient. Dogs are sometimes hyper. _______. Both are effective communicators in their own right. Either one would make any lucky owner happy.
(A) Both animals are fun.(B) Cats are normally calm and resigned.(C) Reptiles are good pets as well.(D) Owners must teach pets how to act.

The paragraph presented compares cats and dogs by first presenting a general aspect about both followed by one characteristic of dogs "Dogs are loving and playful", then one characteristic of cats "Cats are clean and self-sufficient" and another characteristic of dogs " Dogs are sometimes hyper" before moving to the common aspects of both.

This shows the author of this paragraph is comparing and contrasting cats and dogs by explaining first the features of each type of pet. Additionally, in this section, the author has provided 2 aspects related to dogs and just 1 related to cats. Because of this, to make the paragraph complete and in balance, another aspect related to cats need to be added and therefore, the sentence that would create an effective paragraph is "Cats are normally calm and resigned".