This question contains Statement-1 and Statement-2. Of the four choices given after the statements, choose the one that best describes the two statements.
Statement 1: The temperature dependence of resistance is usually given as $R=R_0(1+\alpha \Delta t)$. The resistance of a wire changes from $100\Omega$ to $150\Omega$ when its temperature is increased from $27^{\circ }\text{C}$ to $227^{\circ }\text{C}$. This implies that $\alpha =2.5\times 10^{-3}{/}^{\circ }\text{C}$.
Statement 2: $R=R_i(1+\alpha \Delta T)$ is valid only when the change in the temperature $\Delta T$ is small and $\Delta R=(R-R_0)\ll R_0$.

1. A
   Statement-1 is true, Statement-2 is true; Statement-2 is the correct explanation of Statement-1.
2. B
   Statement-1 is true, Statement-2 is true; Statement-2 is not the correct explanation of Statement-1.
3. C
   Statement-1 is true, Statement-2 is false.
4. D
   Statement-1 is false, Statement-2 is true.