The circuit diagram depicts a battery with electromotive force (e.m.f.) $9.0\,\text{V}$ and negligible internal resistance. It is linked to two resistors with resistances $160\,\Omega$ and $R$. The output potential difference $V_{\text{out}}$ is $4.0\,\text{V}$. Determine the resistance $R$.
- A$32\,\Omega$
- B$49\,\Omega$
- C$71\,\Omega$
- D$128\,\Omega$