1. The problem statement, all variables and given/known data In which diagram(s) (labeled A - D) does the ammeter correctly measure the current through the battery? 2. Relevant equations I don't believe there are any here, just to know that the ammeter is in series with the current that is passing through it and is measuring that current. 3. The attempt at a solution The thing is I'm not sure where the current is coming out of, would I be correct in saying the emf is the source of the current throughout the whole of the battery? If that was the case I was thinking the only current that the ammeter is in series with with battery C but that answer was incorrect (masteringphysics), or would it be that the ammeter is in series with the potential difference measured by the voltmeters? any help is greatly appreciated.