The diagram illustrates a circuit containing a battery with electromotive force (e.m.f.) $60\text{ V}$ and negligible internal resistance, a $20\text{ k}\Omega$ resistor, a thermistor and a voltmeter. The thermistor has a resistance of $20\text{ k}\Omega$. Its temperature falls, causing its resistance to alter by $50\%$. Following this change, what value does the voltmeter show?
- A$20\text{ V}$
- B$24\text{ V}$
- C$36\text{ V}$
- D$40\text{ V}$