Serum sickness and the Arthus reaction are both type III hypersensitivities, but they differ in that

A. serum sickness is a localized reaction to an injected therapy, whereas the Arthus reaction is systemic.

B. serum sickness is vomiting and diarrhea in response to animal serum, whereas the Arthus reaction causes arthritis.

C. serum sickness is an infection in the blood serum, whereas the Arthus reaction is a swelling in the joints.

D. serum sickness is a systemic reaction to an injected therapy, whereas the Arthus reaction remains localized to the injection site.