The correct answer is A.
She is being honest and direct in this response to a difficult situation. By responding in this way she is letting her friends know exactly how she feels about the situation without being angry or harsh or mean, just direct. With any luck her friends will now understand and stop pressurizing her.
The best answer for the blood vessels' valves would be these are veins that would then help in preventing the back flow of blood because the walls have small muscle to pump the blood back to the heart.Hope this is the answer.