The answer is B: Response to stimuli
what response to stimuli means is that the organism reacts to something around it
the venus flytrap wouldn't just randomly close for no reason
it had to sense the fly, and react by closing.
it's not permeability because permeability means allowing things to pass through like soaking up water
unless your teacher is referring to absorbing the nutrients of the dead fly after it's been killed
but I don't think that's what this question is about
:)