A battery with electromotive force (e.m.f.) $6.0\,\text{V}$ and negligible internal resistance is joined in series to a resistor of resistance $6.0\,\Omega$ and a variable resistor whose resistance can vary from zero to $4.0\,\Omega$. A voltmeter is placed across the variable resistor. The resistance of the variable resistor is adjusted. What range of readings can the voltmeter show?
- A$0\,\text{V} - 2.4\,\text{V}$
- B$0\,\text{V} - 3.6\,\text{V}$
- C$2.4\,\text{V} - 6.0\,\text{V}$
- D$3.6\,\text{V} - 6.0\,\text{V}$