Select the letter of the sentence that is most accurate using the proper rules of English grammar and MLA style.

a. Service animals are beneficial because they provide companionship, offer emotional and physical support, and they are affordable.
b. Service animals are beneficial because they provide companionship, emotional and physical support are important, and they are affordable.
c. Service animals are beneficial because they provide companionship, offer emotional and physical support, and deliver affordable care.
d. Service animals are beneficial because they make good pals, they listen when you're crying, and they don't cost very much.