Who should make the first move after a long silent treatment: the one imposing the silence, or the one receiving it?

I had a conversation today with two coworkers about Person A and Person B…
Person A, along with her buddies, have treated Person B as nonexistent for 5 years due to a very slight misunderstanding. Person B has dealt with the silent treatment by avoiding confrontation and just letting it go (she never expected it to last this long). Person A and her buddies have no idea who Person B really is- they only know what they ‘believe’ to be true.
One coworker is of the opinion that person B has a responsibility to break the ice and “show them who she really is,” and “prove that she’s not that bad.”
Another coworker said, no, Person A is the initiator of the silent treatment, so she should be the one the break the ice.
Person A has asked me for my opinion on this… but I am not sure.
Your thoughts?