An iron block of mass $M$ is heated, and its internal energy increases by $10\,\text{kJ}$. The rise in temperature of the block is $\theta\,^{\circ}\text{C}$. Another iron block of mass $2M$ is heated, and its internal energy increases by $5.0\,\text{kJ}$. Determine the temperature rise of the second block in $^{\circ}\text{C}$.
- A$\frac{\theta}{4}$
- B$\frac{\theta}{2}$
- C$2\theta$
- D$4\theta$