Bitching

There is a certain dilemma in my life that has come about many times in my life that has different courses of actions and it mostly isn't clear on which is best.
What do you do when someone bitches about your friend behind their back?
 Do you:
a) Not say a word and just politely say you think they are wrong
b) Stick up for friend as if it were you being bitched about and proceed to report back to friend
c) Jack shit.

Now this has recently happened to a friend of mine. I took action B purely because if someone I was disillusioned to think was nice was talking about me behind my back, I would want to know.
I do not care if my friend confronts them and it all gets chased back to me. They should have known better not to bitch in front of their mate or just not to bitch Full Stop.

However speaking to another friend about this situation she said it might not have been the best thing to do as it could bring the victim down knowing that people think that and they could end up in a spiral of despair thinking no-one likes them. Now personally I know/stongly hope that this friend is stronger than that and they have even said that they will turn their insecurity into hatred for the Bitchers! Go Friend-whose-online-name-shall-not-be-mentioned.

So I thought I did the right thing anyways. Just something for you all to think about.