A filament in a $240\,\text{V}$, $100\,\text{W}$ electric lamp is heated from room temperature to its working temperature. During this warming, its resistance increases by a factor of 16. What is the resistance of the filament at room temperature?
- A$36\,\Omega$
- B$580\,\Omega$
- C$1.5\,\text{k}\Omega$
- D$9.2\,\text{k}\Omega$