A. Components A and B should not trap the error, allowing it to propagate to the client for handling there

B. Component A should try to handle the error and if it can't, pass it up to component B, which will try to handle the error. If it also can't deal with the error, it will translate the error message in terms of itself and pass it up to the client.

C. Component B should in no situation pass an error up to component A