Which sentences are written using a formal style?

Select all that apply.

A. Of the 6.5 million pets that are in shelters, about 3 million are adopted each year.

B. The number of pets in shelters has been declining, but it’s still higher than lots of people would want it to be.

C. My family adopted a dog from the local shelter, and we’re just crazy about her.

D. While pets who are adopted at an older age may have some unknown problems, the opportunity to save a life is compelling to many pet owners.