In rheumatoid arthritis, the body’s immune system misfunctions by atta

According to the passage, the new medication is only inhibiting the hormones that cause pain and swelling i.e. it does not heal the attacked cells by the misfunctioning immune system, at least we don't know from the passage. Option A is, therefore, mentioning more than we can deduce from the passage.

C, on the other hand, can be deduced because the hormones that also get triggered after an injury will be inhibited, the person may sustain injury without being aware of it.

P - what happens in RA = Body immune system > attach healthy cells > release hormone > cause swelling
P - Injury caused > hormone released
C - New medicine > limit or prevent the release of hormone
Prethinking = if Injury causes Hormone to release, maybe the new med will not let the brain to get a signal about a injury, thus hormone wont be released

(A) Unlike aspirin and other medications that reduce pain and swelling and that are currently available, the new medication would repair existing cell damage that had been caused by rheumatoid arthritis. = We dont know about current meds and what they do, and even we dont know if the new med will heal the cells or not!

(B) The benefits to rheumatoid arthritis sufferers of the new medication would outweigh the medications possible harmful side effect. = How do we know? Incorrect

(C) A patient treated with the new medication for rheumatoid arthritis could sustain a joint injury without becoming aware of it. = Exactly! Correct

(D) The new medication could be adapted for use against a variety of immune system disorders, such as diabetes and lupus. = out of scope

(E) Joint diseases other than rheumatoid arthritis would not be affected by the new medication. = Out of scope