Generally depending on the antibiotic they target the phospholipids on the plasma membrane of the bacteria in your system that is making you sick I say bacteria viruses generally mutate so frequently that their phospholipids cannot be targeted which is why when you have the flu all that can cure you is time, you can only hide the symptoms.
Answer:
Let's break this down a bit.
#A (not letting others define you) is actually a healthy boudary, so that can't be it.
#C (speaking up when you are treated poorly) is definately a Healthy boundary too, so it's not C.
and #D (giving only as much as you are comfortable with) is yet another Healthy boundary.
#B (feeling bad when you say no) Is an unhealthy behavieral (can't spell:) ) trait, and if your answer isn't A,C, or D, then it's B. Sorry if I seemed belittling, it took me a sad amount of time to figure it out so I thought I'd explaine it.
I hope it helps!
#B Is Correct
Explanation: