Answer:
I'm assuming the joint pain was related to a homeostatic imbalance. I believe the answer is C.
Explanation:
A is wrong but not false. Your kidneys (and other organs) can be affected, but the patient said that the doctor told them their pain will start to go away and they'll reach homeostasis. They didn't mention a problem with getting there.
Option B is patently false.
Option D is a little silly. Same sort of reasons with A.