Some resistors and a battery of electromotive force (e.m.f.) 
and negligible internal resistance are connected in series, as shown.
Which statement is correct?
The e.m.f. across each resistor equals the potential difference across the battery.
The potential difference across each resistor equals the e.m.f. of the battery.
The sum of the e.m.f.s across the resistors equals the potential difference across the battery.
The sum of the potential differences across the resistors equals the e.m.f. of the battery.
