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:
He must find his average heart rate zone
